NTA Abhyas JEE Main2020PhysicsWork, Power and EnergyPractice
The power supplied by a force acting on a particle moving in a straight line is constant. The velocity of the particle varies with the displacement x as
Options
- Ax 1 / 2
- Bx
- Cx 2
- Dx 1 / 3
Correct answer
D. x 1 / 3
Step-by-step solution
P = F v = ma v = m d 2 x d t 2 d x d t Since, power is constant d 2 x d t 2 d x d t = k or d d t d x d t 2 = k d x d t 2 = k 1 t d x d t = k 1 t d x d t = k 2 t 1 / 2 ∵ k 1 1 / 2 = k 2 x = k 3 t 3 / 2 ∵ k 3 = 2 3 k 2 Hence d x d t ∝ t 1 / 2 ∝ x 1 / 3