Question

A baseball of mass 0.25 kg is hit at home plate with a speed of 40 m/s. When it lands in a seat in the left-field bleachers a horizontal distance 120 m from home plate, it is moving at 30 m/s. If the ball lands 20 m above the spot where it was hit, how much work is done on it by air resistance?

a) 200 J
b) 300 J
c) 250 J
d) 350 J

Answer 1

The work done on the baseball by air resistance is zero.

Step-by-step explanation:

To find the work done on the baseball by air resistance, we need to consider the change in its mechanical energy. The initial mechanical energy of the baseball is given by the sum of its kinetic energy and potential energy. The final mechanical energy of the baseball is also the sum of its kinetic energy and potential energy at the landing position.

The work done on the baseball by air resistance is equal to the difference in the mechanical energies:

Work = (Initial Mechanical Energy) - (Final Mechanical Energy)

Since we're ignoring air resistance, the mechanical energy remains constant and the work done by air resistance is zero. Therefore, the answer is 0 J.