Question 1

Billy swims to a point straight across a 100. m wide river that flows at 1.2 m/s. How long does it take him to swim to the other side?

Accepted Answer

The answer of Billy swims to a point straight across...

Question 2

An airplane with an airspeed of 120. km/h is headed 30.0° East of North in a wind blowing due West at 30. km/h. What is the groundspeed of the plane?

Accepted Answer

The answer of An airplane with an airspeed of 120....

Question 3

Two vectors A and B have components (0, 1, 2) and (-1, 3, 1), respectively. 
(a) Determine the components of the sum of these two vectors. 
(b) Determine the magnitude of the sum of these two vectors.

Accepted Answer

(a) (-1, 4

Question 4

At what angle should a water-gun be aimed in order for the water to land with the greatest horizontal range?

Accepted Answer

A)  30° 
B)  0° 
C)   $\pi$ radians 
D)  90° 
E)  45° 
A)  30° 
B)  0° 
C)   $\pi$ radians 
D)  90° 
E)  45°

Question 5

A stone is thrown horizontally from the top of a tower at the same instant that a ball is dropped vertically. Which object is traveling faster when it hits the level ground below?

Accepted Answer

A)  It is impossible to tell from the information given. 
B)  the ball 
C)  the stone 
D)  Neither, since both are traveling at the same speed. 
A)  It is impossible to tell from the information given. 
B)  the ball 
C)  the stone 
D)  Neither, since both are traveling at the same speed.

Question 6

If vector  = -3.0 x  - 4.0 y  , and vector  = +3.0 x  -8.0 y , then the magnitude of  =  -   is

Accepted Answer

A)  144 
B)  16 
C)  7.2 
D)  3.0 
E)  13.4 
A)  144 
B)  16 
C)  7.2 
D)  3.0 
E)  13.4

Question 7

If the acceleration of an object is always directed perpendicular to its velocity, then

Accepted Answer

A)  the object is t rest. 
B)  the object is slowing down. 
C)  the object is speeding up. 
D)  the object is turning. 
E)  this situation would not be physically possible. 
A)  the object is t rest. 
B)  the object is slowing down. 
C)  the object is speeding up. 
D)  the object is turning. 
E)  this situation would not be physically possible.

Question 8

A boat has a velocity 12. km/hr Southward and 16. km/hr Westward. What is its speed and how long does it take to travel 94. km?

Accepted Answer

20. km/hr

Question 9

A girl throws a stone straight down from a bridge. The stone leaves her hand with speed of 8.00 m/s at a height of 12 m above the water below. How much time does it take for the stone to hit the water?

Accepted Answer

A)  0.41 s 
B)  17.3 s 
C)  0.95 s 
D)  1.8 s 
E)  2.58 s 
A)  0.41 s 
B)  17.3 s 
C)  0.95 s 
D)  1.8 s 
E)  2.58 s

Question 10

A vector A has components Ax > 0, and Ay < 0, the angle that this vector makes with the positive x-axis must be in the range

Accepted Answer

A)  0° to 90°. 
B)  90° to 180°. 
C)  180° to 270°. 
D)  270° to 360°. 
A)  0° to 90°. 
B)  90° to 180°. 
C)  180° to 270°. 
D)  270° to 360°.

Question 11

A car travels east and its velocity decreases. The acceleration of the car is in which of the following directions?

Accepted Answer

A)  Westward 
B)  Northward 
C)  Eastward 
D)  Southward 
E)  Downward 
A)  Westward 
B)  Northward 
C)  Eastward 
D)  Southward 
E)  Downward

Question 12

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water? (use g = 10 m/s2)

Accepted Answer

A)  14 m 
B)  16 m 
C)  24 m 
D)  20 m 
E)  12 m 
A)  14 m 
B)  16 m 
C)  24 m 
D)  20 m 
E)  12 m

Question 13

-Given the three vectors in Figure 3-7, determine the vector sum  +  +  .

Accepted Answer

-19^x -8^y (20

Question 14

A ball thrown horizontally from a point 24 m above the ground strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown? (in this problem use g = 10 m/s2)

Accepted Answer

A)  7.40 m/s 
B)  8.13 m/s 
C)  8.96 m/s 
D)    g 
E)  6.10 m/s 
A)  7.40 m/s 
B)  8.13 m/s 
C)  8.96 m/s 
D)    g 
E)  6.10 m/s

Question 15

It is possible for the resultant of three vectors to equal zero.

Accepted Answer

A) True 
 B)False

Question 16

If A-B=C and A-B=C, then the vectors A and B are oriented perpendicular relative to one other.

Accepted Answer

A) True 
 B)False

Question 17

A vector   has components Ax = 12.0 m and Ay = 5.00 m. What is the angle that vector   makes with the x-axis?

Accepted Answer

A)  32.6° 
B)  12.6° 
C)  22.6° 
D)  6.6° 
E)  42.8° 
A)  32.6° 
B)  12.6° 
C)  22.6° 
D)  6.6° 
E)  42.8°

Question 18

If you increase the initial speed of a bullet by 10%, the resultant RANGE will increase by what percent (assume air resistance can be ignored)?

Accepted Answer

A)  11% 
B)  5.0% 
C)  20% 
D)  21% 
E)  10% 
A)  11% 
B)  5.0% 
C)  20% 
D)  21% 
E)  10%

Question 19

You are serving the volleyball for the second time in a volleyball game. If the ball leaves your hand with twice the velocity it had on your first serve, its horizontal range R (compared to your first serve) would be

Accepted Answer

A)    times as much. 
B)  twice as much. 
C)  2   times as much. 
D)  four times as much. 
E)  half as much. 
A)    times as much. 
B)  twice as much. 
C)  2   times as much. 
D)  four times as much. 
E)  half as much.

Question 20

A package of supplies is dropped from a plane, and one second later a second package is dropped. Neglecting air resistance, the relative velocity of the 1st package viewed from the second will

Accepted Answer

A)  be constant. 
B)  increase. 
C)  decrease. 
D)  be zero. 
E)  depend upon their weight. 
A)  be constant. 
B)  increase. 
C)  decrease. 
D)  be zero. 
E)  depend upon their weight.

Exam 3: Motion in Two Dimensions

Billy swims to a point straight across a 100. m wide river that flows at 1.2 m/s. How long does it take him to swim to the other side?

An airplane with an airspeed of 120. km/h is headed 30.0° East of North in a wind blowing due West at 30. km/h. What is the groundspeed of the plane?

Two vectors A and B have components (0, 1, 2) and (-1, 3, 1), respectively. (a) Determine the components of the sum of these two vectors. (b) Determine the magnitude of the sum of these two vectors.

At what angle should a water-gun be aimed in order for the water to land with the greatest horizontal range?

A stone is thrown horizontally from the top of a tower at the same instant that a ball is dropped vertically. Which object is traveling faster when it hits the level ground below?

If vector = -3.0 x - 4.0 y , and vector = +3.0 x -8.0 y , then the magnitude of vector= - 11eea3ce_f582_45ef_97f4_e39aa9df0df9_TB9720_11 is

If the acceleration of an object is always directed perpendicular to its velocity, then

A boat has a velocity 12. km/hr Southward and 16. km/hr Westward. What is its speed and how long does it take to travel 94. km?

A girl throws a stone straight down from a bridge. The stone leaves her hand with speed of 8.00 m/s at a height of 12 m above the water below. How much time does it take for the stone to hit the water?

A vector A has components Ax > 0, and Ay < 0, the angle that this vector makes with the positive x-axis must be in the range

A car travels east and its velocity decreases. The acceleration of the car is in which of the following directions?

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water? (use g = 10 m/s2)

-Given the three vectors in Figure 3-7, determine the vector sum + + .

A ball thrown horizontally from a point 24 m above the ground strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown? (in this problem use g = 10 m/s2)

It is possible for the resultant of three vectors to equal zero.

If A-B=C and A-B=C, then the vectors A and B are oriented perpendicular relative to one other.

A vector has components Ax = 12.0 m and Ay = 5.00 m. What is the angle that vector 11eea3cd_97cf_6a5c_97f4_87e191913ebf_TB9720_11 makes with the x-axis?

If you increase the initial speed of a bullet by 10%, the resultant RANGE will increase by what percent (assume air resistance can be ignored)?

You are serving the volleyball for the second time in a volleyball game. If the ball leaves your hand with twice the velocity it had on your first serve, its horizontal range R (compared to your first serve) would be

A package of supplies is dropped from a plane, and one second later a second package is dropped. Neglecting air resistance, the relative velocity of the 1st package viewed from the second will

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If vector = -3.0 ^x - 4.0 ^y , and vector = +3.0^x -8.0 ^y, then the magnitude of vector= - 11eea3ce_f582_45ef_97f4_e39aa9df0df9_TB9720_11 is

A vector A has components A_x > 0, and A_y < 0, the angle that this vector makes with the positive x-axis must be in the range

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water? (use g = 10 m/s²)

A ball thrown horizontally from a point 24 m above the ground strikes the ground after traveling horizontally a distance of 18 m. With what speed was it thrown? (in this problem use g = 10 m/s²)

A vector has components A_x = 12.0 m and A_y = 5.00 m. What is the angle that vector 11eea3cd_97cf_6a5c_97f4_87e191913ebf_TB9720_11 makes with the x-axis?