InterviewSolution
Saved Bookmarks
| 1. |
13) A girl having amass of 50 kg sits on a trolley of mass 10 kg. The trolley is given an initial velocityof 5 m/sec by applying a force. The trolley comes to rest after traversing a distance of 12.5 metre.a) How much work is done by the girl?b) How much work is done on the trolley? |
|
Answer» mass of girl = 50kg mass of trolley = 10kg Total mass,m= (50+10) = 60 kg u =5m/s,v= 0,s= 12.5 m. Using kinematics equation,v2=u2+ 2as ⇒ 0 = (5)2+ 2a(12.5) ⇒ 25a= –25 ⇒a= –1m/s2 Force exerted on trolley, F =ma= 60×1 = 60N (a) Work done on trolley W = FS = (60N) (12.5 m) = 750J (b) Work done by the girl, W = FS = (mass of girl) × retardation × S = 50 × 1 × 12.5 = 625 J thank you |
|