Question

Answer the above with clear steps.​

Answer 1

Question :-

A body is pulled by a horizontal force . If the coefficient of friction is 0.25, then find the Frictional force exerted by the horizontal force on the block.

To Find :-

The Frictional force exerted by the horizontal force on the body.

Given :-

• Mass of the body = 20 kg.

• Coefficient of Friction = 0.25.

• Acceleration due to gravity (On earth) = 9.8 m/s².

We know :-

Frictional force :-

$\boxed{\underline{\over{\bf{f_{k} = \mu_{k} R}}}}$

Where :-

• $\bf{f_{k}}$ = Static Friction

• $\bf{\mu_{k}}$ = Coefficient of friction

• R = Normal Reaction force

Normal reaction force :-

$\boxed{\underline{\bf{R = mg}}}$

Where :-

• R = Normal Reaction force

• m = Mass of the body

• g = Acceleration due to Gravity

Concept :-

We know that, Frictional force is directly proportional to the Reaction force , so first we will find the Reaction force of the body.

After that using the formula , we can find the required value .

Solution :-

To Find the Normal Reaction force :-

Given :-

• m = 20 kg

• g = 9.8 m/s²

Using the formula and substituting the values in it, we get :-

$:\implies \bf{R = mg} \\ \\ \\ :\implies \bf{R = 20 \times 9.8} \\ \\ \\ \bf{R = 196} \\ \\ \\ :\therefore \purple{\bf{R = 196 N}}$

Hence, the normal reaction force is 196 N.

To Find the Frictional force :-

Given :-

• R = 196 N

• $\mu$ = 0.25

Using the formula and substituting the values in it , we get :-

$:\implies \bf{f_{k} = \mu_{k} R} \\ \\ \\ :\implies \bf{f_{k} = 0.25 \times 196} \\ \\ \\ :\implies \bf{f_{k} = 49 } \\ \\ \\ \therefore \purple{\bf{f_{k} = 49 N}}$

Hence, the Frictional force exerted by the horizontal force is 49 N.