Question

A cat weighs 50N. I lift it so that it accelerates at a rate of 2m/s2. How much lifting force am I applying to the cat?

Answer 1

The mass of a car

$$m=\frac{W}{g}=\frac{50\:\rm N}{10\:\rm N/kg}=5\:\rm kg.$$

The Newton's second law says

$$ma=F_{\rm lift}-W.$$

Hence, the lift force

$$F_{\rm lift}=ma+W=\\ =(5\:\rm kg)\times (2\:\rm m/s^2)+(50\:\rm N)=60\:\rm N.$$