Ncert Solutions Class 9 Science Chapter 10 Work and Energy - Physicskund
Ncert Solutions Class 9 Science Chapter 10 Work and Energy - Physicskund Example 10.1 A force of 5 N is acting on an object. The object is displaced through 2 m in the direction of the force (Fig. 10.2). If the force acts on the object all through the displacement, then work done is ? Solution: Given Force = 5N , Displacement = 2m Work = Force × Displacement W = 5 N × 2 m =10 N m or 10 J. Page 115 1. A force of 7 N acts on an object.The displacement is, say 8 m, in the direction of the force (Fig. 10.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case? Solution : Work done = Force × displacement W = F × S W = 7 × 8 W= 56 J Example 10.2 A porter lifts a luggage of 15 kg from the ground and puts it on his head 1.5 m above the ground.Calculate the work done by him on the luggage. Solution: Work done = F × s = mg × s W= 15 kg × $10 m s^{-2}$ × 1.5m W=225 $kgms^{-2}$ Page 116 1. When do we say that work is done? Soluti...