Question

In the given figure, when $F=2N$, the frictional force between $5kg$ block and ground is :

• A. $2N$
• B. $0N$
• C. $8N$
• D. $10N$

Answer 1

The correct option is A $2N$

When F is applied, friction force between 5 kg and 10 kg block is

$f=\mu mg=0.1\times 10\times 10=10N$

which is more than the applied force $F=2N$

And the friction force at the ground is $0.3\times (10+5)\times 10=45N$

which is also more than the applied force, so no block will move. Therefore friction force between 5 kg and the ground would be equal to the applied force to satisfy equilibrium which is equal to $2N$.