Question

What is the amount of work done by a person when

1. he holds a mass of 2 kg for 5 second and
2. he lifts the same mass through 1 meter to keep it on the top of a table? g = 9.8 m/s²

विकल्प

• 4.9 J and zero

• zero and 4.9 J

• zero and 19.6 J

• 19.6 J and zero

Answer 1

zero and 19.6 J

Explanation:

In the first case, there is no displacement. Hence work done is zero.

In the second case, work done

W = mgh = 2 × 9.8 × 1 = 19.6 J