Question

A pail of water of mass 5.0 kg is suspended from a weighing scale hanging from the ceiling of a lift.What is the reading of the scale when the lift moves downward at a deceleration of 4ms^-2

Answer 1

$$N-mg=-ma,$$ $$N=m(g-a)=5.0\ kg\cdot(9.8\ \dfrac{m}{s^2}-4.0\ \dfrac{m}{s^2})=29\ N.$$