A 200 gram ball gets dropped from a roof at 15 meters high. A boy on the ground catches it. If 10 percent is translated to internal energy, then what was the increase of internal energy? Is it safe to be playing ball from the roof top?
To determine the increase in internal energy, we need to know the amount of kinetic energy converted into internal energy. We can calculate the initial kinetic energy of the ball using the formula:
Kinetic Energy = (1/2) * mass * velocity^2
Given that the mass of the ball is 200 grams (0.2 kg) and it is dropped from rest, the initial velocity is 0 m/s. Plugging these values into the formula, we find:
Initial Kinetic Energy = (1/2) * 0.2 kg * (0 m/s)^2 = 0 Joules
Since the ball is caught by the boy on the ground, its final velocity is also 0 m/s. Therefore, the final kinetic energy is also 0 Joules. The decrease in kinetic energy is equal to the increase in internal energy, which is 10 percent of the initial kinetic energy.
Increase in Internal Energy = 10% * Initial Kinetic Energy
= 10% * 0 Joules
= 0 Joules
Therefore, the increase in internal energy is 0 Joules. This means that no internal energy was gained by the ball during its fall, as all the initial kinetic energy was converted into potential energy due to the gravitational force acting on it.
Regarding whether it is safe to play ball from the rooftop, there are other important factors to consider such as the height of the roof, the distance from the potential landing spot, the presence of any obstacles, and the potential risk of injury. While this specific energy calculation shows that no internal energy is gained during the ball's fall, it is generally not safe to play ball from rooftops due to the risk of injury from falls or ball impact. It is advisable to play ball in designated areas or appropriate playing fields to ensure safety.