Question

A 72N force accelerates mass (m1) by 5.0 m/s2. The same force acts on another mass (m2) and imparts to it an acceleration of 20.0 m/s2. What accelerates will the same force impart to the two masses when they are joined together?

Answer 1

According to newton's second law;

$F=ma$

Therefore; $M1=\frac{F}{a}=\frac{72}{5}=14.4kg$

$M_2=\frac{5}{20}M_1=\frac{5}{20}\times14.4=3.6kg$

$a=\frac{F}{(M_1+M_2)}=\frac{72}{(14.4+3.6)}=4m/s^2$