Saved Bookmarks
| 1. |
A force of 1 N acts on a body of mass 0.5 kg initially at rest. The ratio of the works done by the force in the first, second and third second is : |
|
Answer» 1:2:3 Also`a=1//0.5=2 ms^(-2)` VELOCITY after one second `v_1=0+2xx1=2 ms^(-1)` Similarly`v_2=0+2xx2=4 ms^(-1)` `v_3=0+2xx3=6 ms^(-1)` Change in K.E. after 1 second `E_1=1/2xx0.5(4-0)=1 J` Similarly `E_2=1/2xx0.5(16-4)=3J` `E_3=1/2xx0.5(36-16)=5 J` Now work done = Change in K.E. `:.` Required RATIO for FIRST three second will be `E_1:E_2:E_3` or `1:3:5` |
|