A 10 kg rock is pushed off the edge of a bridge 50 meters above the groundWhat was the kinetic energy of the rock at the midway point of its fall?

Answer 1

zero

Answer 2

The kinetic energy of the rock at the halfway point of its fall would be equal to the potential energy it had at the beginning, since energy is conserved in the absence of non-conservative forces like air resistance. At the midway point, the rock would have converted half of its potential energy to kinetic energy, so its kinetic energy would be equal to half of its potential energy at the start.

Answer 3

In order to calculate the answer we require the velocity of the mass as it hits the water.

This can be found using the simple equations of motion where we have a constant acceleration.

As such we can use:

V2 = U2 + 2AS

Where:

V = Final velocity (m/s)

U = Initial Velocity (m/s)

A = Acceleration (m/s/s)

S = Distance (m)

The initial velocity is 0, the acceleration is due to gravity (9.81 ms-2) and the distance equals 25m.

As such:

V2 = 02 + (2 x 9.81 x 25)

V2 = 0 + (490.5)

V = Sqrt(490.5)

V = 22.15 m/s

Kinetic energy (EK):

EK = 1/2MV2

(0.5x12) x 22.152

Kinetic Energy = 2,940 joules

Answer 4

The potential energy is mgh where m = 12kg, g = 9.814 m/s/s and h = 25 m. Kinetic energy = potential energy = (12)(9.814)(25) = 2944 joules

Answer 5

2,450 joules

Answer 6

It is approx 2900 Joules.

Answer 7

2,940

Answer 8

zero

Answer 9

2450