Answer to Question #165915 in Physics for shihab

Question

(a) A body of mass 60 kg rests on the floor of a lift (take g=10ms^-2). Calculate:

 

(i)   the reaction force exerted on the body by the floor of the lift, when the lift is travelling at a steady speed of 5 ms^-1 upwards;     

(i)   the reactive force exerted on the body by the floor of the lift, as its upward motion is brought to rest by a constant deceleration of 2 ms^-2.                                               

Answer 1

1)

$$N=mg=(60)(9.8)=588\ N$$

2)

$$N=m(g-a)=(60)(9.8-2)=468\ N$$