Question 1

An object starts its motion with a constant velocity of 2.0 m/s toward the east.After 3.0 s,the object stops for 1.0 s.The object then moves toward the west a distance of 2.0 m in 3.0 s.The object continues traveling in the same direction,but increases its speed by 1.0 m/s for the next 2.0 s.Which graph below could represent the motion of this object?

Accepted Answer

D

Question 2

The motion of a particle is described in the velocity versus time graph shown in the figure.We can say that its speed

Accepted Answer

D

Question 3

An object is moving in a straight line along the x-axis.A plot of its velocity in the x direction as a function of time is shown in the figure.Which graph represents its acceleration in the x direction as a function of time?

Accepted Answer

C

Question 4

If the acceleration of an object is negative,the object must be slowing down.

Accepted Answer

Negative acceleration (deceleration) means the acceleration is in the opposite direction of the velocity. If the object is moving in the negative direction, negative acceleration will actually speed it up.

Question 5

The figure represents the velocity of a particle as it travels along the x-axis.At what value (or values)of t is the instantaneous acceleration equal to zero?

Accepted Answer

The answer of The figure represents the velocity of a...

Question 6

The graph in the figure shows the position of an object as a function of time.The letters H-L represent particular moments of time.At which moments shown (H,I,etc.)is the speed of the object
(a)the greatest?
(b)the smallest?

Accepted Answer

The answer of The graph in the figure shows the...

Question 7

The figure shows the graph of the position x as a function of time for an object moving in the straight line (the x-axis).Which of the following graphs best describes the velocity along the x-axis as a function of time for this object?

Accepted Answer

The answer of The figure shows the graph of the...

Question 8

A ball is thrown directly upward and experiences no air resistance.Which one of the following statements about its motion is correct?

Accepted Answer

When the ball is thrown upward, it experiences a force of gravity pulling it down towards the earth. This force of gravity causes the acceleration of the ball to be downward during the entire time the ball is in the air, regardless of whether it is traveling upward or downward. Therefore, choice C is correct. Choices A, B, and D are incorrect as they suggest that the acceleration changes direction at some point during the ball's motion, which is not true.

Question 9

Suppose that a car traveling to the west (the -x direction)begins to slow down as it approaches a traffic light.Which statement concerning its acceleration in the x direction is correct?

Accepted Answer

Since the car is slowing down while moving to the west (the -x direction), its velocity is negative. To slow down, the acceleration must be in the opposite direction of the velocity, which means the acceleration is positive in this context.

Question 10

An object is moving with constant non-zero acceleration along the +x-axis.A graph of the velocity in the x direction as a function of time for this object is

Accepted Answer

The answer of An object is moving with constant non-zero...

Question 11

Suppose that an object is moving with constant nonzero acceleration.Which of the following is an accurate statement concerning its motion?

Accepted Answer

Velocity is the rate of change of displacement. Since the object is accelerating, its velocity is changing with time. Hence, in equal times, its velocity changes by equal amounts.

Question 12

The motions of a car and a truck along a straight road are represented by the velocity-time graphs in the figure.The two vehicles are initially alongside each other at time t = 0.At time T,what is true about these two vehicles since time t = 0?

Accepted Answer

The answer of The motions of a car and a...

Question 13

Two objects are thrown from the top of a tall building and experience no appreciable air resistance.One is thrown up,and the other is thrown down,both with the same initial speed.What are their speeds when they hit the street?

Accepted Answer

Since both objects have the same initial speed and experience the same gravitational acceleration, they will both reach the street with the same speed. The direction of their initial velocity does not affect their final velocity. Therefore, they will be traveling at the same speed when they hit the street.

Question 14

The figure shows the velocity of a particle as it travels along the x-axis.What is the direction of the acceleration at t = 0.5 s?

Accepted Answer

At t = 0.5 s, the velocity is decreasing (from positive to negative) which means that the acceleration is in the opposite direction of the velocity, i.e. in the -x direction.

Question 15

If the graph of the position as a function of time for an object is a horizontal line,that object cannot be accelerating.

Accepted Answer

A horizontal line on a position-time graph indicates that the position of the object is not changing with respect to time. As acceleration is defined as the rate at which an object's velocity changes over time, an object with a constant position cannot be accelerating. Therefore, the statement is true.

Question 16

Two objects are dropped from a bridge,an interval of 1.0 s apart,and experience no appreciable air resistance.As time progresses,the DIFFERENCE in their speeds

Accepted Answer

Since both objects are in free fall and experience no air resistance, they both accelerate at the same rate due to gravity. This means the difference in their speeds remains constant over time.

Question 17

When can we be certain that the average velocity of an object is always equal to its instantaneous velocity?

Accepted Answer

The average velocity of an object is equal to its instantaneous velocity only when the velocity is constant. When the object's velocity is changing, the instantaneous velocity can be different at different times, making it different from the average velocity. Therefore, we can be certain that the average velocity is always equal to the instantaneous velocity only when the velocity is constant.

Question 18

Which one of the following graphs could possibly represent the vertical position as a function of time for an object in free fall?

Accepted Answer

In free fall, an object experiences a constant acceleration due to gravity. This means the position-time graph should be a quadratic function, with a steep increase in position at the beginning (when the object is dropped or released), slowing down as it approaches the ground. Option D is the only graph that fits this description.

Question 19

The figure shows the position of an object (moving along a straight line)as a function of time.Assume two significant figures in each number.Which of the following statements about this object is true over the interval shown?

Accepted Answer

The answer of The figure shows the position of an...

Question 20

If an object is accelerating toward a point,then it must be getting closer and closer to that point.

Accepted Answer

Acceleration refers to the rate of change of velocity, which can include changes in speed or direction. An object can be accelerating toward a point even if it is moving in a circular path around that point, maintaining a constant distance from it.

Quiz 2: Motion Along a Straight Line