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Use energy to find the ball\'s maximum height above the ground. Express your ans

ID: 1480889 • Letter: U

Question

Use energy to find the ball's maximum height above the ground. Express your answer to two significant figures and include the appropriate units. A boy reaches out of a window and tosses a ball straight up with a speed of 14 m/s . The ball is 17 m above the ground as he releases it. Use energy to find the ball's speed as it passes the window on its way down. Express your answer to two significant figures and include the appropriate units. Use energy to find the speed of impact on the ground. Express your answer to two significant figures and include the appropriate units.

Explanation / Answer

by conservation of energy

initial energy = final energy

mgh + 0.5 * mv^2 = mgh1

gh + 0.5 * v^2 = gh1

9.8 * 17 + 0.5 * 14^2 = 9.8 * h1

h1 = 27 m

Hmax = 27 m

mg * Hmax = mgh + 0.5 * mv^2

g * Hmax = gh + 0.5 * v^2

9.8 * 27 = 9.8 * 17 + 0.5 * v^2

v = 14 m/s

g * Hmax = 0.5 * v^2

9.8 * 27 = 0.5 * v^2

speed of impact on the ground v = 23 m/s