InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
When a `2` kg car driven at `20 m//s` on a level road is suddenly put into netural gear (i.e. allowed to coast), the velocity decreases in the following manner: `V=20/(1+(t/20))m//s` Where t is time in sec. The deceleration of car at the instant its speed is `10 m//s` is.A. `1//4 m//s^(2)`B. `1//2 m//s^(2)`C. `1 m//^(2)`D. `3//4 m//s^(2)` |
|
Answer» Correct Answer - A Given that initial velocity `=u=20 m//s` `v=20/(1+t/20)` at `u=10 m//s` `10/1=20/(1+t/20)` `2=1+t/20` `t=t/20` `t=20` sec From `u=20/(1+t/20)=400/(20+t)` acceleration `a=(dv)/(dt)=400xx1/((20+t)^(2))` acceleration `a=(-400)/(40xx40)` acceleration `a=(-1)/4 m//s^(2)` so deceleration `a=1/4 m//s^(2)` |
|