Question

What will the kinetic energy of a pile driver ram be if it starts from rest and undergoes a 10 kJ decrease in potential energy?

Answer 1

`KE_f = 10 kJ`

Step-by-step explanation:

As per mechanical energy conservation law we can say that sum of kinetic energy and potential energy will always remains constant

so here we can say

`KE_i + PE_i = KE_f + PE_f`

here we have

`KE_i = 0`

as initially it starts from rest

so now we have

`KE_f = PE_i - PE_f`

now we know that its final potential energy is decreased by 10 kJ

so we have

`PE_f = PE_i - 10 kJ`

`PE_i - PE_f = 10 kJ`

so the final kinetic energy will be

`KE_f = 10 kJ`