AP Physics 1 midterm

A block of mass is at rest on a rough incline, as shown in the figure above. Which of the following forces must have a magnitude equal to ? Select two answers.

• The total force exerted on the block by the incline

• The normal force exerted on the block by the incline

• The force of friction exerted on the block by the incline

• The gravitational force exerted on Earth by the block

A projectile fired into the air explodes and splits into two halves of equal mass that hit the ground at the same time. If the projectile had not exploded, it would have landed at point X, which is a distance R to the right of the launch point. After the explosion, one of the halves lands at point Y, which is a distance 2R to the right of the launch point. If air resistance is negligible, where did the other half land?

• To the left of the launch point

• At the launch point

• Between the launch point and point X

• Between points X and Y

Four rods, each of mass , are pinned at the left end to the horizontal surface of a table and are shown from above in the following figures. Each rod is free to rotate about a pivot at its left end with negligible friction. In each case, forces are exerted on the rod with different magnitudes and in different directions as shown. The rotational inertia of a rod of mass and length about the end of the rod is . In which cases do the rods experience equal initial angular accelerations? Select two answers.

• A

• B

• C

• D

The angular momentum of a rigid body rotating around a fixed point as a function of time is shown in the graph. Which of the following statements are true? Select two answers.

• The angular speed of the object is constant.

• The angular acceleration of the object is constant.

• The angular position of the object is constant.

• The net torque applied to the object is constant.

In a classroom at time t = 0 , a sphere is thrown upward at a 45° angle to the horizontal. At time t1, while the sphere is still rising, it bounces off the ceiling elastically and with no friction. Which of the following pairs of graphs could

represent the sphere’s horizontal velocity and vertical velocity as functions of time t?

• A

• B

• C

• D

A vertical spring launcher is attached to the top of a block and a ball is placed in the launcher, as shown in the figure. While the block slides at constant speed to the right across a horizontal surface with negligible friction between the block and the surface, the ball is launched upward. When the ball reaches its maximum height, what will be the position of the ball relative to the spring launcher?

• Above and to the right of the spring launcher

• Directly above the spring launcher

• Above and to the left of the spring launcher

• The relative position of the ball depends on the horizontal speed of the block.