A baseball pitcher throws a 250g baseball to make it accelerate to 50 m/s the instant that it leaves his hand. How much energy (in Joules) is expended (how much work is done) if that same baseball travels a distance of 30 meters?

1 answer

The work done on an object can be calculated using the equation W = F * d * cos(theta), where W is the work done, F is the force applied, d is the distance traveled, and theta is the angle between the applied force and the direction of motion.

In this case, we need to determine the force applied to the baseball in order to accelerate it to 50 m/s. We can use Newton's second law, F = ma, where m is the mass of the baseball and a is the acceleration.

Given that the baseball has a mass of 250g (or 0.25kg) and accelerates to 50 m/s, the force applied can be calculated as F = 0.25kg * 50m/s^2 = 12.5 N.

The work done on the baseball in traveling a distance of 30 meters can now be calculated as W = F * d * cos(theta). Since the angle between the applied force and the direction of motion is generally assumed to be zero, cos(theta) = 1.

Therefore, W = 12.5 N * 30 m * 1 = 375 J.

The amount of energy (in Joules) expended or work done on the baseball is 375 J.