Question

The work done by a man in lifting an object of mass 5 kg to a height 50 cm from the ground level is ( g = 10 ms ^-2) ___________.
1. 25 N
2. 2500 J
3. 25 J
4. 2.5 J

Answer 1

Correct Answer - Option 3 : 25 J

The correct answer is 25 J.

• Work is the product of the component of the force in the direction of the displacement and the magnitude of this displacement.
• The dimension of work is the same as that of energy and is given as, [ML²T^-2].
• The SI unit of work is the joule (J), which is defined as the work done by a force of 1 Newton in moving an object through a distance of 1 meter in the direction of the force.

⇒Work done = Force * displacement

⇒Force = Mass * Acceleration,

⇒Force = 5 x 10

⇒Force = 50 N.

So, Work done = 50 Newtons * 0.5 meter

⇒Work done = 25 J.