Exam 2: Motion, Forces, and Newtons Laws

A v-t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 6 s the acceleration of the ball is zero. We know that at t = 6 s,

On a position-time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval $\Delta$ t, is which of the following quantities?

A 50-g ball traveling at 25.0 m/s is bounced off a brick wall and rebounds at 20.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.50 ms, what is the magnitude of the average acceleration of the ball during this time interval?

When we add a displacement vector to another displacement vector, the result is:

The net force on an object in the positive x direction. Consider the following statements: i) The object can be moving in the negative x direction. ii. The object can be speeding up. iii. The object can be slowing down. iv. The object can be moving in the positive y direction. Which of the statements are true?

In one-dimensional motion where the direction is indicated by a plus or minus sign, the average velocity of an object has which of the following properties?

A truck moves 70 m west, then moves 120 m east, and finally moves west again a distance of 90 m. If east is chosen as the positive direction, what is the truck's resultant displacement?

A particle moves east at constant velocity for a time interval t. It then moves north at a constant velocity, with the same speed as before, for another time interval t Finally it moves east again with the original velocity. At the instant an additional time interval t has elapsed, which of the following are true about the average velocity and the average acceleration for the motion described?

An object is dropped from a height. Once it is moving, which of the following statements is true, at least at one point?

An object moves 20 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the sign associated with the average velocity of the object?

A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100 km/hr in 8.00 s. If so, what is the acceleration? (Hint: First convert speed to m/s.)

A hiker walks 200 m east and then walks 100 m north. In what direction is her resulting displacement?

Suppose a particle is moving along a straight line with a speed v for a time t, then stops for a time t, and then resumes moving along the original direction with speed v for time t. What has been the average speed of the particle for the total time period 3t?

The distance of the Earth from the Sun is 93,000,000 miles. If there are 3.15 *10⁷ s in one year, find the speed of the Earth in its orbit about the Sun.

An automobile of mass 2000 kg moving at 20 m/s is braked suddenly with a constant braking force of 10,000 N. How far does the car travel before stopping?

On a position-time graph for a particle, suppose the plot starts at some positive position and as the time goes on the curve gets steeper and steeper while curving upwards. Which of the following must be true?

The slope of the acceleration-time curve represents:

A ball is pushed downhill with an initial velocity of 3.0 m/s. The ball rolls down a hill with a constant acceleration of 1.6 m/s². The ball reaches the bottom of the hill in 6.0 s. What is the ball's velocity at the bottom of the hill?

A European sports car dealer claims that his product will accelerate at a constant rate from rest to a speed of 100 km/hr in 8.00 s. What is the speed after the first 5.00 s of acceleration? (Hint: First convert the speed to m/s.)

An object moves at a constant velocity of 12 m/s to the southwest for an interval of 20 s. Halfway through this interval, what is the magnitude of its instantaneous velocity?