Question

Two bodies having the same mass, 21kg each have different surface areas 50 m${}^2$ and 100 m${}^2$ in contact with a horizontal plane. If the coefficient of friction is 0.2, the forces of friction that come into play when they are in motion will be in the ratio.

• A. 1:1
• B. 1:2
• C. 2:1
• D. 1:4

Answer 1

The correct option is A 1:1

The friction is not dependent on the surface area of friction.

$F=\mu N$

$\mu -$ coefficient of friction

$N-$ Normal Force

Therefore,

$f_1={\mu }_1{m}_1$ and $f_2={\mu }_2{m}_2$

${\mu }_1={\mu }_2$ and $m_1=m_2=21kg$

Hence, $\frac{f_1}{f_2}=1:1$