Answer:
Velocity of throwing = 34.335 m/s
Explanation:
Time taken by the tennis ball to reach maximum height, t = 0.5 x 7 = 3.5 seconds.
Let the initial velocity be u, we have acceleration due to gravity, a = -9.81 m/s² and final velocity = 0 m/s
Equation of motion result we have v = u + at
Substituting
0 = u - 9.81 x 3.5
u = 34.335 m/s
Velocity of throwing = 34.335 m/s
Answer: 88.2 J
Explanation: PE, OR Potential Energy, equals to mass gravity and height.
mass - 3kg
height - 3 because (8-5)
gravity is 9.8kg
so 3 times 3 times 9.8 = 88.2J
That's wave 'diffraction'.