Question

A block of mass $1kg$ lies on a horizontal surface in a truck. The coefficient of friction between the block and the surface is $0.6$. If the acceleration of the truck is $5m{s}^{-2}$, the frictional force acting on the block is

• A. $5N$
• B. $10N$
• C. $15N$
• D. $20N$

Answer 1

Answer: (A)

$5N$

As the mass is rest on a truck , when the truck is moving with acceleration $5m/s^2$, the mass will experience a

force $F=ma=1\left(5\right)=5N$

Generally friction force $f=\mu mg=0.6\times 1\times 10=6N$

Since the mass is lies on the truck so the required friction force will be $f=F=5N$ (friction force oppose the force applied).