Question

a 2 kg box on the ground is lifted to a height of 4 m by a person. How much energy does the box have after being lifted?

Answer 1

Answer:

78.4 J energy is needed to lift the box

Explanation:

We can calculate the potential energy of objects above ground  level using the  potential energy equation . which  id given by

$PE=mgh$

Here m=mass of object =2 kg

h=height from ground level = 4 m

$PE=mgh\\PE=2 \times\99.8 \times 4\\PE=78.4 J$

Work done is nothing but   change in potential energy

78.4 J energy is needed to lift the box