Conservation of Energy (College Board AP® Physics 1: Algebra-Based): Exam Questions

A projectile is fired from level ground with speed  at an angle  to the ground, where . The projectile is fired from a few centimeters before position , reaches its maximum height at position , and lands on the ground at position

The energy bar charts in Figure 1 represent the gravitational potential energy and the kinetic energy of the projectile as it passes through positions , and . The bar chart at position is complete. Draw shaded rectangles to complete the energy bar charts in Figure 1 for positions and .

• Positive energy values are above the zero-energy line.

• Shaded regions should start at the dashed line representing zero energy.

• Represent any energy that is equal to zero with a distinct line on the zero-energy line.

• The relative height of each shaded region should reflect the magnitude of the respective energy consistent with the scale shown.

Figure 2

Figure 1

In Experiment 1, a block is initially at position and in contact with, but not attached to, an uncompressed spring of negligible mass. The block is pushed back along a frictionless surface from position to , as shown in Figure 1. The block compresses the spring by an amount . The block is then released. At the block enters a rough part of the track and eventually comes to rest at position . The coefficient of kinetic friction between the block and the rough track is .

On Figure 2, sketch and label graphs of both the kinetic energy, , of the block and the potential energy, , of the block as a function of position between and . You do not need to calculate values for the vertical axis, but the same vertical scale should be used for both quantities.

Figure 2