99 Percentile Qs Bank for JEE MainPhysicsMotion in One Dimension
A car moving with a velocity (6.25 ~ms ⁻¹ ) is decelerated with (2.5 v ms ⁻² ) ( (v ) is instantaneous velocity). Time taken by the car to come to rest is
Options
- A(2 ~s )
- B(3 ~s )
- C(2.5 ~s )
- D(4 ~s )
Correct answer
A. (2 ~s )
Step-by-step solution
Given, (u=6.25 ~ms ⁻¹ ) and (a=-2.5 v ~ms ⁻² ), (v= ) instantaneous velocity As we know, (a= d v d t ) So, ( d v d t =-2.5 v ) Integrate on the both sides, we get ( array llrl & _ 6.25 ^0 1 v d v & =-2.5 d t & [2 v ]_ 6.25 ^0 & =-2.5 t & t & = 2 2.5 2.5 =2 ~s array ) Hence, the correct option is (a).