Deck 3: Kinematics in Two Dimensions

Question 1

A block is at rest on a rough inclined plane and is connected to an object with the same mass as shown.The rope may be considered massless; and the pulley may be considered frictionless.The coefficient of static friction between the block and the plane is µ_s; and the coefficient of kinetic friction is $\mu$ _k.

-A park ranger wanted to measure the height of a tall tree.The ranger stood 9.50 m from the base of the tree; and he observed that his line of sight made an angle of 65.2° above the horizontal as he looked at the top of the tree.The park ranger's eyes are 1.80 m above the ground.What is the height of the tree?

A)5.84 m
B)8.77 m
C)11.7 m
D)17.3 m
E)22.4 m

Answer 1

22.4 m

Question 2

At time t = 0 s, a puck is sliding on a horizontal table with a velocity 3.60 m/s, 35.0° above the +x axis.As the puck slides, a constant acceleration acts on it that has the following components: a_x = -0.360 m/s² and a_y = -0.980 m/s².What is the velocity of the puck at time t = 1.50 s?

A)1.83 m/s, 12.0° above the +x axis
B)2.04 m/s, 21.2° above the +x axis
C)1.06 m/s, 11.7° above the +x axis
D)2.48 m/s, 13.9° above the +x axis
E)1.38 m/s, 15.2° above the +x axis

Answer 2

2.48 m/s, 13.9° above the +x axis

Question 3

A car travels due east at 22 m/s.It makes a turn due south and continues to travel at 22 m/s. What is the change in velocity of the car?

A)22 m/s, due east
B)22 m/s, due south
C)31 m/s, 45° south of west
D)31 m/s, 45° south of east
E)zero m/s

Answer 3

31 m/s, 45° south of west

Question 4

3-1
During a one-hour trip, a small boat travels 80.0 km north and then travels 60.0 km east.
What is the boat's average speed during the one-hour trip?

A)20 km/h
B)100 km/h
C)140 km/h
D)280 km/h
E)10 000 km/h

Question 5

A baseball is hit upward and travels along a parabolic arc before it strikes the ground.Which one of the following statements is necessarily true?

A)The acceleration of the ball decreases as the ball moves upward.
B)The velocity of the ball is zero m/s when the ball is at the highest point in the arc.
C)The acceleration of the ball is zero m/s² when the ball is at the highest point in the arc.
D)The x-component of the velocity of the ball is the same throughout the ball's flight.
E)The velocity of the ball is a maximum when the ball is at the highest point in the arc.

Question 6

What is the direction of the boat's average velocity for the one-hour trip?

A)due east
B)36.9° north of east
C)41.7° north of east
D)49.2° north of east
E)53.1° north of east

Question 7

3-2
A spaceship is observed traveling in the positive x direction with a speed of 150 m/s when it begins accelerating at a constant rate.The spaceship is observed 25 s later traveling with an instantaneous velocity of 1500 m/s at an angle of 55° above the +x axis.
What was the magnitude of the displacement of the spaceship during the 25 seconds?

A)2.0 × 10⁴ m
B)1.4 × 10⁴ m
C)2.8 × 10⁴ m
D)1.0 × 10⁴ m
E)1.7 × 10² m

Question 8

A train travels due south at 60 m/s.It reverses its direction and travels due north at 60 m/s. What is the change in velocity of the train?

A)120 m/s, due north
B)120 m/s, due south
C)60 m/s, due north
D)60 m/s, due south
E)zero m/s

Question 9

A physics student standing on the edge of a cliff throws a stone vertically downward with an initial speed of 10.0 m/s.The instant before the stone hits the ground below, it is traveling at a speed of 30.0 m/s.If the physics student were to throw the rock horizontally outward from the cliff instead, with the same initial speed of 10.0 m/s, what is the magnitude of the velocity of the stone just before it hits the ground?

A)10.0 m/s
B)20.0 m/s
C)30.0 m/s
D)40.0 m/s
E)The height of the cliff must be specified to answer this question.

Question 10

A tennis ball is thrown from ground level with velocity directed 30° above the horizontal.If it takes the ball 0.5 s to reach the top of its trajectory, what is the magnitude of the initial velocity?

A)4.9 m/s
B)9.8 m/s
C)11.3 m/s
D)19.6 m/s
E)34.4 m/s

Question 11

A GPS tracking device is placed in a police dog to monitor its whereabouts relative to the police station.At time t₁ = 23 min, the dog's displacement from the station is 1.2 km, 33° north of east.At time t₂ = 57 min, the dog's displacement from the station is 2.0 km, 75° north of east.Find the magnitude and direction of the dog's average velocity between these two times.

A)0.52 m/s, 88° north of east
B)1.4 m/s, 31° west of north
C)1.6 m/s, 42° north of east
D)0.67 m/s, 21° west of north
E)0.80 m/s, 42° west of north

Question 12

3-1
During a one-hour trip, a small boat travels 80.0 km north and then travels 60.0 km east.
What is the magnitude of the boat's average velocity for the one-hour trip?

A)20 km/h
B)100 km/h
C)140 km/h
D)10 000 km/h
E)20 000 km/h

Question 13

A car travels along a highway with a velocity of 24 m/s, west.The car exits the highway; and 4.0 s later, its instantaneous velocity is 16 m/s, 45° north of west.What is the magnitude of the average acceleration of the car during the four-second interval?

A)2.4 m/s²
B)4.5 m/s²
C)1.2 m/s²
D)11 m/s²
E)17 m/s²

Question 14

A delivery truck leaves a warehouse and travels 2.60 km north.The truck makes a left turn and travels 1.25 km west before making another right turn to travel 1.40 km north to arrive at its destination.What is the magnitude and direction of the truck's displacement from the warehouse?

A)4.00 km, 18.2° north of west
B)5.25 km, 59.8° north of west
C)6.33 km, 70.2° north of west
D)3.40 km, 55.0° north of west
E)4.19 km, 72.6° north of west

Question 15

3-1
During a one-hour trip, a small boat travels 80.0 km north and then travels 60.0 km east.
What is the boat's displacement for the one-hour trip?

A)20 km
B)100 km
C)140 km
D)280 km
E)10 000 km

Question 16

An eagle is flying due east at 8.9 m/s carrying a gopher in its talons.The gopher manages to break free at a height of 12 m.What is the magnitude of the gopher's velocity as it reaches the ground? Note: effects of air resistance are not included in this calculation.

A)22 m/s
B)18 m/s
C)11 m/s
D)9.8 m/s
E)8.9 m/s

Question 17

A toolbox is carried from the base of a ladder at point A as shown in the figure.The toolbox comes to a rest on a scaffold 5.0 m above the ground.What is the magnitude of the displacement of the toolbox in its movement from point A to point B?

A)15 m
B)19 m
C)8.1 m
D)11 m
E)13 m

Question 18

An airplane traveling north at 400 m/s is accelerated due east at a rate of 50 m/s² for 6 s.If the effects of air resistance and gravity are ignored, what is the final speed of the plane?

A)300 m/s
B)400 m/s
C)500 m/s
D)700 m/s
E)800 m/s

Question 19

A football is kicked at an angle $\theta$ with respect to the horizontal.Which one of the following statements best describes the acceleration of the football during this event if air resistance is neglected?

A)The acceleration is zero m/s² at all times.
B)The acceleration is 9.8 m/s² at all times.
C)The acceleration is zero m/s² when the football has reached the highest point in its trajectory.
D)The acceleration is positive as the football rises, and it is negative as the football falls.
E)The acceleration starts at 9.8 m/s² and drops to some constant lower value as the ball approaches the ground.

Question 20

3-2
A spaceship is observed traveling in the positive x direction with a speed of 150 m/s when it begins accelerating at a constant rate.The spaceship is observed 25 s later traveling with an instantaneous velocity of 1500 m/s at an angle of 55° above the +x axis.
What was the magnitude of the acceleration of the spaceship during the 25 seconds?

A)1.5 m/s²
B)7.3 m/s²
C)28 m/s²
D)48 m/s²
E)57 m/s²

Question 21

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
A quarterback throws a pass at an angle of 35° above the horizontal with an initial speed of 25 m/s.The ball is caught by the receiver 2.55 seconds later.Determine the distance the ball was thrown.

A)13 m
B)18 m
C)36 m
D)52 m
E)72 m

Question 22

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
What is the magnitude of the acceleration of the shell just before it strikes the ground?

A)4.0 m/s²
B)9.8 m/s²
C)82 m/s²
D)170 m/s²
E)330 m/s²

Question 23

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
What is the magnitude of the velocity of the shell as it hits the ground?

A)4.0 m/s
B)9.8 m/s
C)82 m/s
D)170 m/s
E)330 m/s

Question 24

A tennis ball is thrown upward at an angle from point A.It follows a parabolic trajectory and hits the ground at point D.At the instant shown, the ball is at point B.Point C represents the highest position of the ball above the ground.
While in flight, how do the x and y components of the velocity vector of the ball compare at the points B and C?

A)The velocity components are non-zero at B and zero at C.
B)The x components are the same; the y component at C is zero m/s.
C)The x components are the same; the y component has a larger magnitude at C than at B.
D)The x component is larger at C than at B; the y component at B points up while at C, it points downward.
E)The x component is larger at B than at C; the y component at B points down while at C, it points upward.

Question 25

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
Determine the initial speed of the projectile.

A)40 m/s
B)50 m/s
C)60 m/s
D)70 m/s
E)80 m/s

Question 26

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
An arrow is shot horizontally from a height of 4.9 m above the ground.The initial speed of the arrow is 45 m/s.Neglecting friction, how long will it take the arrow to hit the ground?

A)9.2 s
B)6.0 s
C)1.0 s
D)1.4 s
E)4.6 s

Question 27

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
A basketball is launched with an initial speed of 8.0 m/s and follows the trajectory shown.The ball enters the basket 0.96 s after it is launched.What are the distances x and y? Note: The drawing is not to scale. x y

A)5.4 m 0.73 m
B)7.7 m 0.91 m
C)5.4 m 0.91 m
D)5.7 m 0.73 m
E)5.4 m 5.4 m

Question 28

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
Determine the initial speed of the shell.

A)4.0 m/s
B)9.8 m/s
C)82 m/s
D)170 m/s
E)330 m/s

Question 29

3-5
A shell is fired with a horizontal velocity in the positive x direction from the top of an 80-m high cliff.The shell strikes the ground 1330 m from the base of the cliff.The drawing is not to scale.
A cannonball at ground level is aimed 30.0° above the horizontal and is fired with an initial speed of 125 m/s.How far away from the cannon will the cannonball hit the ground?

A)125 m
B)138 m
C)695 m
D)1040 m
E)1380 m

Question 30

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
What is the magnitude of the projectile's velocity just before it strikes the ground?

A)zero m/s
B)9.8 m/s
C)30 m/s
D)40 m/s
E)50 m/s

Question 31

A spring-loaded gun is aimed horizontally and is used to launch identical balls with different initial speeds.The gun is at a fixed position above the floor.The balls are fired one at a time. If the speed of the second ball fired is twice the speed of the first ball fired, how is the horizontal range (denoted R in the figure) affected?

A)The range for both balls will be the same.
B)The range of the second ball will be half as much as that of the first ball.
C)The range of the second ball will be twice as large as that of the first ball.
D)The range of the second ball is about 1.4 times larger than that of the first ball.
E)The range of the second ball will be smaller than that of the first ball by a factor of 1.4.

Question 32

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
What is the acceleration of the projectile when it reaches its maximum height?

A)zero m/s²
B)9.8 m/s², downward
C)4.9 m/s², downward
D)less than 9.8 m/s² and non-zero.
E)Its magnitude is 9.8 m/s²; and its direction is changing.

Question 33

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
At what angle is the projectile fired (measured with respect to the horizontal)?

A)37°
B)40°
C)45°
D)53°
E)60°

Question 34

3-3
A projectile is fired at an angle of 55.0° above the horizontal with an initial speed of 35.0 m/s.
What is the magnitude of the horizontal component of the projectile's displacement at the end of 2 s?

A)30 m
B)40 m
C)10 m
D)20 m
E)50 m

Question 35

A puck slides across a smooth, level tabletop at height H at a constant speed v_o.It slides off the edge of the table and hits the floor a distance x away as shown in the figure. What is the relationship between the distances x and H?

A)
B)
C)
D)
E)

Question 36

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
What is the speed of the projectile when it is at the highest point in its trajectory?

A)0 m/s
B)20 m/s
C)30 m/s
D)40 m/s
E)50 m/s

Question 37

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
A projectile is fired horizontally with an initial speed of 57 m/s.What are the horizontal and vertical components of its displacement 3.0 s after it is fired? horizontal vertical

A)44 m -29 m
B)170 m zero m
C)170 m -44 m
D)210 m -44 m
E)210 m zero m

Question 38

3-4
A projectile fired from a gun has initial horizontal and vertical components of velocity equal to 30 m/s and 40 m/s, respectively.
Approximately how long does it take the projectile to reach the highest point in its trajectory?

A)1 s
B)2 s
C)4 s
D)8 s
E)16 s

Question 39

A bullet is aimed at a target on the wall a distance L away from the firing position.Because of gravity, the bullet strikes the wall a distance $\Delta$ y below the mark as suggested in the figure. Note: The drawing is not to scale. If the distance L was half as large and the bullet had the same initial velocity, how would $\Delta$ y be affected?

A)( $\Delta$ y will double.)
B)( $\Delta$ y will be half as large.)
C)( $\Delta$ y will be four times larger.)
D)( $\Delta$ y will be one fourth as large.)
E)( $\Delta$ y is not possible to determine unless numerical values are given for the distances.)

Question 40

3-3
A projectile is fired at an angle of 55.0° above the horizontal with an initial speed of 35.0 m/s.
How long does it take the projectile to reach the highest point in its trajectory?

A)1.5 s
B)2.4 s
C)4.0 s
D)6.2 s
E)9.8 s

Question 41

3-11
Two cars approach each other on a straight and level road.Car A is traveling at 75 km/h, due north and car B is traveling at 45 km/h, due south.Both velocities are measured relative to the ground.
What is the velocity of car A relative to an observer in car B?

A)75 km/h, north
B)30 km/h, north
C)30 km/h, south
D)120 km/h, south
E)120 km/h, north

Question 42

A rock is kicked horizontally at a speed of 15 m/s from the edge of a cliff.The rock strikes the ground 65 m from the foot of the cliff of height H as suggested in the figure, which is not drawn to scale.Neglect air resistance.
What is the approximate value of H, the height of the cliff?

A)27 m
B)54 m
C)78 m
D)150m
E)300 m

Question 43

A football is kicked with a speed of 18 m/s at an angle of 65° to the horizontal.
How long is the football in the air? Neglect air resistance.

A)1.1 s
B)1.6 s
C)2.0 s
D)3.3 s
E)4.0 s

Question 44

Which statement is true concerning the ball when it is at C, the highest point in its trajectory?

A)The ball's velocity and acceleration are both zero.
B)The ball's velocity is perpendicular to its acceleration.
C)The ball's velocity is not zero, but its acceleration is zero.
D)The ball's velocity is zero, but its acceleration is not zero.
E)The horizontal and vertical components of the ball's velocity are equal.

Question 45

3-10
During football practice, a football is kicked with a speed of 22 m/s at an angle of 60.0° relative to the positive x direction.At that instant, an observer rides past the football in a car that moves with a constant speed of 11 m/s in the positive x direction.
Complete the following statement: According to the observer in the car, the ball will

A)follow a parabolic path.
B)follow a hyperbolic path.
C)follow a path that is straight up and down in the y direction.
D)follow a path that is straight across in the +x direction.
E)follow a straight line that is angled (less than 90°)with respect to the x direction.

Question 46

A rock is kicked horizontally at a speed of 15 m/s from the edge of a cliff.The rock strikes the ground 65 m from the foot of the cliff of height H as suggested in the figure, which is not drawn to scale.Neglect air resistance.
How long is the rock in the air?

A)1.0 s
B)1.2 s
C)4.0 s
D)5.5 s
E)11.2 s

Question 47

A football is kicked with a speed of 18 m/s at an angle of 65° to the horizontal.
What are the respective horizontal and vertical components of the initial velocity of the football?

A)7.6 m/s, 16 m/s
B)16 m/s, 7.6 m/s
C)8.4 m/s, 13 m/s
D)13 m/s, 8.4 m/s
E)9 m/s, 9 m/s

Question 48

3-11
Two cars approach each other on a straight and level road.Car A is traveling at 75 km/h, due north and car B is traveling at 45 km/h, due south.Both velocities are measured relative to the ground.
At a certain instant, the distance between the cars is 15 km.How long will it take, in seconds, from that instant for the two cars to meet?

A)450 s
B)900 s
C)720 s
D)1200 s
E)1900 s

Question 49

A tennis ball is thrown vertically with an initial speed of 20.0 m/s at time t = 0 s.Approximately, what is the initial speed of the ball relative to an observer in a car that moves horizontally past the launch location with a constant speed of 30 m/s?

A)10 m/s
B)20 m/s
C)30 m/s
D)36 m/s
E)50 m/s

Question 50

A projectile is fired horizontally with an initial speed of 50.0 m/s.Neglect air resistance.
What is the magnitude of the acceleration of the projectile 3.00 s after it is fired?

A)9.8 m/s²
B)16.6 m/s²
C)29.4 m/s²
D)5.42 m/s²
E)zero m/s²

Question 51

3-10
During football practice, a football is kicked with a speed of 22 m/s at an angle of 60.0° relative to the positive x direction.At that instant, an observer rides past the football in a car that moves with a constant speed of 11 m/s in the positive x direction.
Determine the initial velocity of the ball relative to the observer in the car.

A)19 m/s in the +y direction
B)11 m/s in the +y direction
C)19 m/s at 60° to the +x direction
D)33 m/s at 60° to the +x direction
E)17 m/s at 60° to the +x direction

Question 52

At which point is the velocity vector changing most rapidly with time?

A)A
B)B
C)C
D)D
E)It is changing at the same rate at all four points.

Question 53

3-11
Two cars approach each other on a straight and level road.Car A is traveling at 75 km/h, due north and car B is traveling at 45 km/h, due south.Both velocities are measured relative to the ground.
A boat that can travel at 4.0 km/h in still water crosses a river with a current of 2.0 km/h.At what angle must the boat be pointed upstream (that is, relative to its actual path) to go straight across the river?

A)27°
B)30°
C)60°
D)63°
E)90°

Question 54

A tennis ball is thrown upward at an angle from point A.It follows a parabolic trajectory and hits the ground at point D.At the instant shown, the ball is at point B.Point C represents the highest position of the ball above the ground.
While in flight, how do the x and y components of the velocity vector of the ball compare at the points A and D?

A)The velocity components are non-zero at A and are zero m/s at D.
B)The velocity components are the same in magnitude and direction at both points.
C)The velocity components have the same magnitudes at both points, but their directions are reversed.
D)The velocity components have the same magnitudes at both points, but the directions of the x components are reversed.
E)The velocity components have the same magnitudes at both points, but the directions of the y components are reversed.

Question 55

A football is kicked with a speed of 18 m/s at an angle of 65° to the horizontal.
How far does the football travel horizontally before it hits the ground?

A)18 m
B)25 m
C)36 m
D)48 m
E)72 m

Question 56

A motorcycle has a velocity of 24 m/s, due south as it passes a car with a velocity of 15 m/s, due north.What is the magnitude and direction of the velocity of the motorcycle as seen by the driver of the car?

A)9 m/s, north
B)9 m/s, south
C)15 m/s, north
D)39 m/s, north
E)39 m/s, south

Question 57

A projectile is fired horizontally with an initial speed of 50.0 m/s.Neglect air resistance.
What is the magnitude of the displacement of the projectile 3.00 s after it is fired?

A)29.4 m
B)44.1 m
C)150 m
D)156 m
E)194 m

Question 58

3-12
A man at point A directs his rowboat due north toward point B, straight across a river of width 100 m.The river current is due east.The man starts across, rowing steadily at 0.75 m/s and reaches the other side of the river at point C, 150 m downstream from his starting point.
What is the speed of the river?

A)0.38 m/s
B)0.67 m/s
C)1.1 m/s
D)6.7 m/s
E)7.5 m/s

Question 59

3-11
Two cars approach each other on a straight and level road.Car A is traveling at 75 km/h, due north and car B is traveling at 45 km/h, due south.Both velocities are measured relative to the ground.
A ferry can travel at an optimal speed of 8 km/h in still water measured relative to the shore.What is the optimal speed of the ferry, relative to the shore, if it moves perpendicular to a 6 km/h current?

A)4 km/h
B)8 km/h
C)10 km/h
D)14 km/h
E)28 km/h

Question 60

A projectile is fired horizontally with an initial speed of 50.0 m/s.Neglect air resistance.
What is the speed of the projectile 3.00 s after it is fired?

A)29.4 m/s
B)50.0 m/s
C)58.0 m/s
D)79.4 m/s
E)98.6 m/s

Question 61

Airplane One flies due east at 250 km/h relative to the ground.At the same time, Airplane Two flies 325 km/h, 35° north of east relative to the ground.What is the velocity of Airplane One relative to Airplane Two?

A)16 km/h, due west
B)270 km/h, due north
C)210 km/h, 55° south of east
D)170 km/h, 15° north of east
E)190 km/h, 85° south of west

Question 62

A basketball player is running at a constant speed of 2.5 m/s when he tosses a basketball upward with a speed of 6.0 m/s.How far does the player run before he catches the ball? Ignore air resistance.

A)3.1 m
B)4.5 m
C)The ball cannot be caught because it will fall behind the player.
D)6.0 m
E)7.5 m

Question 63

A bicyclist is riding at a constant speed along a straight-line path.The rider throws a ball straight up to a height a few meters above her head.Ignoring air resistance, where will the ball land?

A)behind the rider
B)in front of the rider
C)in the same hand that threw the ball
D)in the opposite hand to the one that threw it
E)This cannot be determined without knowing the speed of the rider and the maximum height of the ball.

Question 64

3-12
A man at point A directs his rowboat due north toward point B, straight across a river of width 100 m.The river current is due east.The man starts across, rowing steadily at 0.75 m/s and reaches the other side of the river at point C, 150 m downstream from his starting point.
Two cars A and B approach each other at an intersection.Car A is traveling south at 20 m/s, while car B is traveling east at 17 m/s.What is the velocity of car A as described by the passengers in car B?

A)37 m/s, eastward
B)26 m/s, 40° south of east
C)26 m/s, 50° south of east
D)26 m/s, 50° south of west
E)26 m/s, 40° south of west

Question 65

3-12
A man at point A directs his rowboat due north toward point B, straight across a river of width 100 m.The river current is due east.The man starts across, rowing steadily at 0.75 m/s and reaches the other side of the river at point C, 150 m downstream from his starting point.
A passenger at rest on a flatbed train car fires a bullet straight up.The event is viewed by observers at rest on the station platform as the train moves past the platform with constant velocity.What is the trajectory of the bullet as described by the observers on the platform?

A)a straight horizontal path in the direction of the train's velocity
B)a straight vertical path up and down
C)a circular path centered on the gun
D)a straight diagonal path
E)a parabolic path

Question 66

On a two lane highway, a car is following a pickup truck.At one instant, the car has a speed of 32 m/s and is 184 m behind the truck.At the same time, the truck has a speed of 28 m/s.If neither vehicle accelerates, how long will it take the car to catch up to the truck?

A)4.8 s
B)24 s
C)46 s
D)82 s
E)96 s

Question 67

3-12
A man at point A directs his rowboat due north toward point B, straight across a river of width 100 m.The river current is due east.The man starts across, rowing steadily at 0.75 m/s and reaches the other side of the river at point C, 150 m downstream from his starting point.
While the man is crossing the river, what is his velocity relative to the shore?

A)1.35 m/s, 34° north of east
B)2.00 m/s, 56° north of east
C)1.74 m/s, 34° north of east
D)2.11 m/s, 34° north of east
E)2.50 m/s, 42° north of east

Question 68

A ball is fired at an angle of 45°, the angle that yields the maximum range in the absence of air resistance.What is the ratio of the ball's maximum height to its range?

A)1.0
B)0.75
C)0.67
D)0.50
E)0.25