Exam 2: Motion in One Dimension

A cart starts from rest and accelerates uniformly at 4.0 m/s² for 5.0 s. It next maintains the velocity it has reached for 10 s. Then it slows down at a steady rate of 2.0 m/s² for 4.0 s. What is the final speed of the car?

A hammer is thrown upward with a speed of 14 m/s on the surface of planet X where the acceleration due to gravity is 3.5 m/s² and there is no atmosphere. What is the speed of the hammer after 8.0 s?

A foul ball is hit straight up into the air with a speed of 30 m/s, and air resistance is negligible. (a) Calculate the time required for the ball to rise to its maximum height. (b) Calculate the maximum height reached by the ball above the point where it hit the bat. (c) Determine the times at which the ball passes a point 25 m above the point where it was hit by the bat. (d) Explain why there are two answers to part (c).

Brick A is dropped from the top of a building. Brick B is thrown straight down from the same building, and neither one experiences appreciable air resistance. Which statement about their accelerations is correct?

A cart with an initial velocity of 5.0 m/s to the right experiences a constant acceleration of 2.0 m/s² to the right. What is the cart's displacement during the first 6.0 s of this motion?

Arthur and Betty start walking toward each other when they are 100 m apart. Arthur has a speed of 3.0 m/s and Betty has a speed of 2.0 m/s. How long does it take for them to meet?

In the absence of air resistance, a ball is thrown vertically upward with initial speed v. An identical ball is thrown upward with initial speed 2v. If the first ball reaches a maximum height h, what maximum height will the second ball reach?

Which of the following situations is impossible?

The graph in the figure shows the position of a particle as it travels along the x-axis. At what value of t is the speed of the particle equal to 0 m/s?

A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct?

Starting from rest, a dragster travels a straight 1/4 mi racetrack in 6.70 s with constant acceleration. What is its velocity when it crosses the finish line?

Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct?

If the acceleration of an object is zero, then that object cannot be moving.

Abby throws a ball straight up and times it. She sees that the ball goes by the top of a flagpole after 0.50 s and reaches the level of the top of the pole after a total elapsed time of 4.1 s. What was the speed of the ball at as it passed the top of the flagpole? Neglect air resistance.

If the velocity of an object is zero at some point, then its acceleration must also be zero at that point.

The figure shows a graph of the position of a moving object as a function of time. What is the velocity of the object at each of the following times? (a) At t = 1.0 s (b) At t = 2.5 s (c) At t = 4.0 s (d) At t = 5.5 s

A toy rocket is launched vertically from ground level at time t = 0.00 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 81 m and acquired an upward velocity of $40 \mathrm{~m} / \mathrm{s}$ The rocket continues to rise with insignificant air resistance in unpowered flight, reaches maximum height, and falls back to the ground. The upward acceleration of the rocket during the burn phase is closest to

A car is able to stop in a distance d. Assuming the same braking force (and therefore the same acceleration), what distance does this car require to stop when it is traveling twice as fast?

If the velocity versus time graph of an object is a horizontal line, the object is

A laser is thrown upward with a speed of 12 m/s on the surface of planet X where the acceleration due to gravity is 1.5 m/s² and there is no atmosphere. What is the maximum height reached by the laser?