Deck 4: The Laws of Motion: Part A

Question 1

A ball is rolled horizontally off a table with an initial speed of 0.18 m/s.A stopwatch measures the ball's trajectory time from table to the floor to be 0.30 s.What is the height of the table? Note: g = 9.8 m/s² and air resistance is negligible.

A) 0.11 m
B) 0.22 m
C) 0.33 m
D) 0.44 m

Answer 1

0.44 m

Question 2

A 4000-N weight is suspended in equilibrium by two cables.Cable 1 applies a horizontal force to the right of the object and has a tension T₁.Cable 2 applies a force upward and to the left at an angle of 37.0° to the negative x axis and has a tension T₂.Find T_2.

A) 4000 N
B) 6650 N
C) 8310 N
D) 3340 N

Answer 2

6650 N

Question 3

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 39.2 m/s at an initial angle of 30.0° with respect to the horizontal.What is the maximum vertical displacement that the ball reaches during its trajectory?

A) 11.0 m
B) 19.6 m
C) 22.1 m
D) 44.1 m

Answer 3

19.6 m

Question 4

A trapeze artist,with swing,weighs 700 N;he is momentarily held to one side by his partner so that the swing ropes make an angle of 30.0° with the vertical.In such a condition of static equilibrium,what is the horizontal force being applied by the partner?

A) 924 N
B) 404 N
C) 808 N
D) 233 N

Question 5

A 200-N crate rests on a ramp;the maximum angle just before it slips is 21° with the horizontal.What is the coefficient of static friction between crate and ramp surfaces?

A) 0.11
B) 0.21
C) 0.38
D) 0.47

Question 6

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 39.2 m/s at an initial angle of 30.0° with respect to the horizontal.If it is in its trajectory for a total of 4.00 s before being caught by the third baseman at an equal shoulder-height level,what is the ball's net vertical displacement during its 4.00-s trajectory?

A) 11.0 m
B) 9.80 m
C) 22.1 m
D) zero

Question 7

A 500-N tightrope walker stands at the center of the rope.If the rope can withstand a tension of 1400 N without breaking,what is the minimum angle the rope can make with the horizontal?

A) 4°
B) 8°
C) 10°
D) 15°

Question 8

A ball is rolled horizontally off a table with an initial speed of 0.18 m/s.A stopwatch measures the ball's trajectory time from table to the floor to be 0.30 s.How far away from the table does the ball land? Note: g = 9.8 m/s² and air resistance is negligible.

A) 0.054 m
B) 0.072 m
C) 1.2 m
D) 1.9 m

Question 9

A trapeze artist,with swing,weighs 700 N;he is being held to one side by his partner so that the swing ropes make an angle of 30.0° with the vertical.In such a condition of static equilibrium what is the tension in the rope?

A) 924 N
B) 404 N
C) 808 N
D) 233 N

Question 10

A 25-g traffic light hangs midway on a cable between two poles 40 meters apart.If the sag in the cable is 0.40 meters,what is the tension in each side of the cable?

A) 12,200 N
B) 9800 N
C) 4900 N
D) 6100 N

Question 11

A 100-kg box is placed on a ramp.As one end of the ramp is raised,the box begins to move downward just as the angle of inclination reaches 25°.What is the coefficient of static friction between box and ramp?

A) 0.15
B) 0.27
C) 0.47
D) 0.95

Question 12

A 200-N block,on a 30° incline,is being held motionless by friction.The coefficient of static friction between the block and the plane is 0.60.The force due to friction is:

A) 104 N.
B) 100 N.
C) 60 N.
D) 0 N.

Question 13

The coefficient of static friction between the tires of a car and the street is µ_s = 0.58.Of the following,what is the steepest inclination angle of a street on which a car can be parked (with wheels locked)without slipping?

A) 22.5°
B) 30°
C) 38°
D) 45°

Question 14

A sled weighs 100 N.It is held in place on a frictionless 30° slope by a rope attached to a stake at the top;the rope is parallel to the slope.What is the normal force acting on the sled?

A) 94 N
B) 87 N
C) 50 N
D) 34 N

Question 15

A sled is on a horizontal surface and a rope with tension T is pulling on it at an angle θ above the horizontal.The sled had mass M and does not move due to the frictional force.In this case the coefficient of friction is μ​_s.In terms of the variables given and g,what is the magnitude of the frictional force in this case?

A) μ​_sMg
B) Tcosθ
C) Tsinθ
D) μ​_sMgcosθ

Question 16

A 500-N tightrope walker stands at the center of the rope such that each half of the rope makes an angle of 15.0° with the horizontal.What is the tension in the rope?

A) 1440 N
B) 970 N
C) 480 N
D) 2900 N

Question 17

A helicopter is traveling at 54 m/s at a constant altitude of 100 m over a level field.If a wheel falls off the helicopter,with what speed will it hit the ground? Note: g = 9.8 m/s² and air resistance is negligible.

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

Question 18

A projectile is fired over a horizontal surface at an angle of elevation of 70°.Neglecting air resistance,what are possible angles in flight between the acceleration vector and the velocity vector?

A) 170° and 40°
B) 120° and 70°
C) 90° and 15°
D) none of the above

Question 19

John throws a baseball from the outfield from shoulder height,at an initial velocity of 39.2 m/s at an initial angle of 30.0° with respect to the horizontal.The ball is in its trajectory for a total interval of 4.00 s before the third baseman catches it at an equal shoulder-height level.(Assume air resistance is negligible. )What is the ball's horizontal displacement?

A) 76.4 m
B) 38.2 m
C) 136 m
D) zero

Question 20

A 4000-N weight is held suspended in equilibrium by two cables.Cable 1 applies a horizontal force to the right of the object and has a tension T₁.Cable 2 applies a force upward and to the left at an angle of 37.0° to the negative x axis and has a tension T₂.What is the tension T₁?

A) 4000 N
B) 6640 N
C) 6250 N
D) 5310 N

Question 21

A rifle is aimed horizontally toward the center of a target 71 m away.If the bullet strikes 10 cm below the center,what was the velocity of the bullet? Note: Ignore air friction.

A) 300 m/s
B) 330 m/s
C) 500 m/s
D) 700 m/s

Question 22

A jet airliner moving at 600 mph due east moves into a region where the wind is blowing at 120 mph in a direction 30.0° north of east.What is the new speed and direction of the aircraft?

A) 706 mph,5.67° N of E
B) 620 mph,5.67° N of E
C) 706 mph,4.87° N of E
D) 588 mph,4.87° N of E

Question 23

A ball is launched from ground level at 30 m/s at an angle of 25° above the horizontal.How far does it go before it is at ground level again?

A) 14 m
B) 70 m
C) 43 m
D) 86 m

Question 24

A baseball is moving in the air along the customary parabola.Ignoring air drag,where is the force on the baseball zero?

A) at the top of the parabola
B) just when it has started upward
C) where it is about to impact
D) nowhere

Question 25

Two baseballs are released at the same time.One is dropped from rest and the other is given an initial horizontal velocity.Which of the following is not true? Ignore atmospheric drag.

A) Both baseballs hit the ground at the same time.
B) Both have the same vertical component of velocity as they reach impact.
C) The horizontal component of velocity increases at a greater rate than the vertical component of velocity for both while they are both in the air.
D) The horizontally-released ball has a greater speed than the other ball for the whole trip.

Question 26

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 40-m building.If g = 9.8 m/s² and air resistance is negligible,then what is the speed of the rock as it hits the ground?

A) 30 m/s
B) 32 m/s
C) 34 m/s
D) 36 m/s

Question 27

A projectile is launched at an angle less than 30° and at speed v.Which will increase the projectile's range more,ignoring atmospheric drag?

A) doubling the launch angle
B) increasing the speed of launch by 50%
C) reducing the mass of the projectile
D) launching on February 29th

Question 28

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 40-m building.If g = 9.8 m/s² and air resistance is negligible,then what is the magnitude of the horizontal component of velocity as the rock strikes the ground?

A) 7.5 m/s
B) 9.0 m/s
C) 12 m/s
D) 29 m/s

Question 29

A projectile is launched with speed v at an angle θ,the angle being less than 45º.What other angle would give the same range for this projectile launched at the same speed v?

A) 2θ
B) 0.5θ
C) 90° - θ
D) 90º - 0.5θ

Question 30

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 40-m building.If g = 9.8 m/s² and air resistance is negligible,what is the magnitude of the horizontal displacement of the rock?

A) 30 m
B) 39 m
C) 66 m
D) 90 m

Question 31

A bridge that was 8.3 m long has been washed out by the rain several days ago.How fast must a car be going to successfully jump the stream? Although the road is level on both sides of the bridge,the road on the far side is 2.0 m lower than the road on this side.

A) 5.0 m/s
B) 7.8 m/s
C) 13 m/s
D) 25 m/s

Question 32

A fireman,40.0 m away from a burning building,directs a stream of water from a fire hose at an angle of 30.0° above the horizontal.If the initial speed of the stream is 40.0 m/s,at what height above the nozzle will the stream of water strike the building?

A) 9.60 m
B) 16.6 m
C) 18.7 m
D) 22.4 m

Question 33

A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 14 m/s.A stop watch measures the stone's trajectory time from top of cliff to bottom to be 7.1 s.How far out from the cliff's edge does the stone travel horizontally? Note: g = 9.8 m/s² and air resistance is negligible.

A) 58 m
B) 68 m
C) 86 m
D) 197 m

Question 34

A baseball leaves the bat with a speed of 44.0 m/s and an angle of 30.0° above the horizontal.A 4.0-m high fence is located at a horizontal distance of 132 m from the point where the ball is struck.Assuming the ball leaves the bat 1.0 m above ground level,by how much does the ball clear the fence?

A) 18.9 m
B) 14.4 m
C) 9.8 m
D) 5.4 m

Question 35

A track star in the broad jump goes into the jump at 10 m/s and launches himself at 20° above the horizontal.How long is he in the air before returning to Earth? Note: g = 9.8 m/s².

A) 0.35 s
B) 0.42 s
C) 0.70 s
D) 0.89 s

Question 36

Wiley Coyote has missed the elusive Road Runner once again.This time,he leaves the edge of the cliff at 40.0 m/s horizontal velocity.If the canyon is 100 m deep,how far from his starting point on the edge of the cliff does the coyote land?

A) 207 m
B) 247 m
C) 339 m
D) 400 m

Question 37

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 40-m building.If g = 9.8 m/s² and air resistance is negligible,then what is the magnitude of the vertical velocity component of the rock as it hits the ground?

A) 30 m/s
B) 24 m/s
C) 26 m/s
D) 29 m/s

Question 38

A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 14 m/s.A stop watch measures the stone's trajectory time from top of cliff to bottom to be 7.1 s.What is the height of the cliff? Note: g = 9.8 m/s² and air resistance is negligible.

A) 58 m
B) 114 m
C) 120 m
D) 197 m

Question 39

A boat moves at 11.0 m/s relative to the water.If the boat is in a river where the current is 2.00 m/s,how long does it take the boat to make a complete round trip of 1000 m upstream followed by a 1000 m trip downstream?

A) 188 s
B) 205 s
C) 208 s
D) 222 s

Question 40

Superguy is flying at treetop level near Paris when he sees the Eiffel Tower elevator start to fall (the cable snapped).His x-ray vision tells him Lois LaTour is inside.If Superguy is 1.00 km away from the tower,and the elevator falls from a height of 2.1 × 10² m,how long does Superguy have to save Lois,and what must be his average speed?

A) 4.5 s,200 m/s
B) 6.5 s,150 m/s
C) 7.0 s,140 m/s
D) 9.0 s,110 m/s

Question 41

A 10-kg mass and a 6.0-kg mass are connected by a light string over a massless,frictionless pulley.If g = 9.8 m/s²,what is the acceleration of the system when released?

A) 2.5 m/s²
B) 6.5 m/s²
C) 7.8 m/s²
D) 9.8 m/s²

Question 42

Plane A is flying at 600 mph in the northeast direction relative to the Earth.Plane B is flying at 500 mph in the north direction relative to the Earth.What is the speed of Plane B as observed from Plane A?

A) 900 mph
B) 431 mph
C) 357 mph
D) 100 mph

Question 43

A plane is moving due north,directly towards its destination.Its airspeed is 200 mph.A constant breeze is blowing from west to east at 40 mph.How long will it take for the plane to travel 200 miles north?

A) one hour
B) more than one hour
C) less than one hour
D) more information is needed

Question 44

A 2000-kg sailboat experiences an eastward force of 2000 N by the ocean tide and a wind force against its sails with magnitude of 6000 N directed toward the northwest (45° N of W).What is the direction of the resultant acceleration?

A) 60° N of E
B) 62° N of W
C) 30° N of E
D) 74° N of W

Question 45

A boat travels upstream and after one hour has gone 10 km.The boat next travels downstream and after one hour has gone 16 km.If the boat's speed relative to the water is constant,what is the speed of the current in the river?

A) 1 km/h
B) 2 km/h
C) 3 km/h
D) 4 km/h

Question 46

A 12.0-kg mass is placed on a 25.0° incline and friction keeps it from sliding.The coefficient of static friction in this case is 0.580,and the coefficient of sliding friction is 0.520.The mass is given a shove causing it to slide down the incline.What is the frictional force while the mass is sliding?

A) 55.4 N
B) 107 N
C) 49.7 N
D) 61.2 N

Question 47

A river flows due east at 2.0 m/s.A boat crosses the 300 m-wide river by maintaining a constant velocity of 10 m/s due north relative to the water.If no correction is made for the current,how far downstream does the boat move by the time it reaches the far shore?

A) 6 m
B) 30 m
C) 60 m
D) 90 m

Question 48

Two ropes are attached to a 40-kg object.The first rope applies a force of 50 N and the second,40 N.If the two ropes are perpendicular to each other,what is the resultant magnitude of the acceleration of the object?

A) 1.2 m/s²
B) 1.6 m/s²
C) 25 m/s²
D) 47 m/s²

Question 49

A 2000-kg sailboat experiences an eastward force of 2000 N by the ocean tide and a wind force against its sails with magnitude of 6000 N directed toward the northwest (45° N of W).What is the magnitude of the resultant acceleration?

A) 2.2 m/s²
B) 2.4 m/s²
C) 1.5 m/s²
D) 3.0 m/s²

Question 50

A 15-kg block rests on a level,frictionless surface and is attached by a light string to a 10-kg hanging mass where the string passes over a massless frictionless pulley.If g = 9.8 m/s²,what is the tension in the connecting string?

A) 65 N
B) 17 N
C) 59 N
D) 37 N

Question 51

A 150-N sled is pulled up a 28° slope at a constant speed by a force of 120 N.What is the coefficient of kinetic friction between sled and slope?

A) 0.53
B) 0.22
C) 0.37
D) 0.33

Question 52

A boxcar of mass 200 tons at rest becomes uncoupled on a 1.5° grade.If the track is considered to be frictionless,what speed does the boxcar have after 10 seconds?

A) 0.37 m/s
B) 0.59 m/s
C) 2.6 m/s
D) 4.3 m/s

Question 53

A plane is moving due north,directly towards its destination.Its airspeed is 200 mph.A constant breeze is blowing from west to east at 42 mph.In which direction is the plane pointed?

A) 5.7° W of N
B) 12° W of N
C) 22° W of N
D) 11° E of N

Question 54

A 12.0-kg mass is placed on a 25.0° incline and friction keeps it from sliding.The coefficient of static friction in this case is 0.580 and the coefficient of sliding friction is 0.520.The mass is given a shove causing it to slide down the incline.Taking down the incline as positive,what is the acceleration of the mass while it is sliding?

A) −1.99 m/s²
B) 1.99 m/s²
C) −0.477 m/s²
D) 0.477 m/s²

Question 55

As I pull a rope connected to a box at constant speed up a frictionless slope,pulling parallel to the slope,the tension in the rope will be:

A) greater than the tension would be if the box were stationary.
B) greater than the weight of the box.
C) equal to the weight of the box.
D) less than the weight of the box.

Question 56

A plane is moving due north,directly towards its destination.Its airspeed is 200 mph.A constant breeze is blowing from west to east at 60 mph.At what rate is the plane moving north?

A) 198 mph
B) 196 mph
C) 191 mph
D) 180 mph

Question 57

The accelerating force of the wind on a small 250-kg sailboat is 707 N northeast.If the drag of the keel is 500 N acting west,what is the acceleration of the boat?

A) 1.5 m/s² due east
B) 2.5 m/s² due north
C) 3.0 m/s² northeast
D) 2.0 m/s² due north

Question 58

Plane A is flying at 600 mph in the northeast direction relative to the Earth.Plane B is flying at 500 mph in the north direction relative to the Earth.What is the direction of motion of Plane B as observed from Plane A?

A) 52.5° N of E
B) 48.2° N of W
C) 37.5° N of W
D) 10.1° N of W

Question 59

A 12-kg mass is placed on a 25.0° incline,and friction keeps it from sliding.The coefficient of static friction in this case is 0.580,and the coefficient of sliding friction is 0.520.What is the frictional force in this situation?

A) 55.4 N
B) 107 N
C) 49.7 N
D) 61.2 N

Question 60

A 250-kg crate is placed on an adjustable inclined plane.If the crate slides down the incline with an acceleration of 0.25 m/s² when the incline angle is 25°,then what should the incline angle be for the crate to slide down the plane at constant speed? Note: g = 9.8 m/s².

A) 12°
B) 21°
C) 24°
D) 29°

Question 61

A box is launched up a frictionless incline with an angle of elevation θ.The maximum height reached by the box is h.The box is again launched up the incline with the same initial speed it had before,but this time the angle of elevation has been increased to φ.How does the maximum height H reached this time by the box compare with the previous value h?

A) H = h
B) H > h
C) H < h
D) H​ = ((sinφ)/(sinθ))

Question 62

A sphere is dropped from a great height and when its speed reaches 20 m/s,its acceleration downward is 8.4 m/s².If the drag force is proportional to the square of the speed,what will be its acceleration downward when its speed reached 40 m/s?

A) 2.6 m/s²
B) 4.2 m/s²
C) 8.0 m/s²
D) 0 m/s² because it has now reached terminal velocity.

Question 63

A 6.0-kg object is falling downward with an acceleration of 3.27 m/s².Of the following values,which is nearest to the drag force on the object?

A) 3.3 N
B) 65 N
C) 20 N
D) 39 N

Question 64

An Olympic skier moving at 22.0 m/s down a 30.0° slope encounters a region of wet snow,of coefficient of friction µ_k = 0.740.How far down the slope does she go before stopping?

A) 119 m
B) 145 m
C) 175 m
D) 199 m

Question 65

A 9.0-kg hanging weight is connected by a string over a pulley to a 5.0-kg block sliding on a flat table.If the coefficient of sliding friction is 0.10,find the tension in the string.

A) 19 N
B) 24 N
C) 35 N
D) 38 N

Question 66

A solid steel ball is dropped from a great height and when its speed reaches 20 m/s its acceleration downward is 7.35 m/s².What would be the terminal velocity in this situation?

A) 80 m/s
B) 60 m/s
C) 40 m/s
D) 20 m/s

Question 67

Jamal pulls a 150-N sled up a 28.0° slope at constant speed by a force of 120 N.Near the top of the hill he releases the sled.With what acceleration does the sled go down the hill?

A) 1.20 m/s²
B) 1.36 m/s²
C) 2.22 m/s²
D) 2.67 m/s²

Question 68

Dana uses a rope to pull a box that weighs 300 N across a level surface with constant velocity.The rope makes an angle of 30° above the horizontal and the tension in the rope is 50 N.What is the coefficient of friction?

A) 0.35
B) 0.29
C) 0.16
D) 0.20

Question 69

A box slides up an incline with an angle of elevation θ.When the box reaches its maximum distance up the incline it stops and does not slide down the incline due to friction.What is the minimum value of the coefficient of static friction for this to occur?

A) μ_s = tanθ
B) μ_s = sinθ
C) μ_s = cosθ
D) μ_s = 1