Question

"A tennis ball has a mass of 7.2 x 10^-2 kg and has an initial speed of 7.7 m/s as it is tossed up into the air from a height of 3.0 m. Calculate the speed of the ball when it hits the ground. Ignore air resistance."

A. 7.7 m/s
B. 3.0 m/s
C. 0 m/s
D. Need more information

Answer 1

To find the speed of the tennis ball when it hits the ground, we can use the principle of conservation of energy. The ball starts with potential energy due to its height above the ground, and this potential energy is converted into kinetic energy as the ball falls.

Step-by-step explanation:

To find the speed of the tennis ball when it hits the ground, we can use the principle of conservation of energy. The ball starts with potential energy due to its height above the ground, and this potential energy is converted into kinetic energy as the ball falls. Since the ball starts from rest at a height of 3.0 m, we can calculate the potential energy: mgh = (7.2 x 10^-2 kg)(9.8 m/s^2)(3.0 m) = 2.11 J. This potential energy is equal to the kinetic energy of the ball just before it hits the ground, so we can set it equal to (1/2)mv^2, where v is the speed of the ball when it hits the ground. Plugging in the values, we get: 2.11 J = (1/2)(7.2 x 10^-2 kg)v^2. Solving for v, we find v = 6.76 m/s.