You drop a ball (initially at rest) from a height of 12 meters above the ground.

Question

You drop a ball (initially at rest) from a height of 12 meters above the ground. You can neglect air resistance. Which statements are true about this situation?
The kinetic energy of the ball is 1/3 of the total energy when the ball is at a height of 2 meters
The minimum value of gravitational potential energy occurs when the ball is at a height of 0 meters
The kinetic energy and the gravitational potential energy of the ball are equal when the ball is at a height of 6 meters
The kinetic energy of the ball will be twice the gravitational potential energy when the ball is at a height of 6 meters
The sum of KE + PE decreases as the ball falls

Please show work

Explanation / Answer

1: total enrgy of ball =m*g*h =m*g*12

at h=2m, K.E=m*g*10 =>K.E is not 1/3 of m*g*12...............false

2: true P.E =m*g*h =>P.E is minimum at minimum h

3:true: P.E at h=6 : m*g*6 =>K.E at h=6 is K.E=m*g*12-m*g*6 =m*g*6

4:false

5: false. sum of KE + PE is always constant

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