A machine which is 75 percent efficient, uses 12 joules of energy in lifting up a 1 kg mass through a certain distance. The mass is then allowed to fall through that distance. The velocity at the end of its fall is (in `ms^(-1)`)

Explanation

To solve the problem step by step, we will follow the principles of energy conservation and the definitions of work, potential energy, and kinetic energy.

### Step 1: Calculate the Work Done by the Machine
The machine is 75% efficient and uses 12 joules of energy. The work done by the machine can be calculated using the formula:
\[ \text{Work Done} = \text{Efficiency} \times \text{Input Energy} \]
Substituting the values:
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