JEE Main2014PhysicsLaws of MotionActual
A body of mass 5 ~kg under the action of constant force F =F_x i +F_y j has velocity at t =0 ~s as v =(6 i -2 j m / s ) and at t =10 ~s as v =+6 j m / s . The force F is:
Options
- A(-3 i +4 j ) N
- B(- 3 5 i + 4 5 j ) N
- C(3 i -4 j ) N
- D( 3 5 i - 4 5 j ) N
Correct answer
A. (-3 i +4 j ) N
Step-by-step solution
From question, Mass of body, m=5 ~kg Velocity at t=0 , u=(6 i -2 j ) m / s Velocity at t=10 ~s , v=+6 j ~m / s Force, F= ? Acceleration, a= v-u t = 6 j -(6 i -2 j ) 10 = -3 i +4 j 5 ~m / s ^2 Force, F=m a =5 (-3 i +4 j ) 5 =(-3 i +4 j ) N