Question

A block of mass $m$ is moving with velocity $v$ on a smooth horizontal surface. If a constant force $F$ is applied to the block, what is the work done by this force after 5 seconds?

• A. $Fv$
• B. $F \cdot 5v$
• C. $\frac{1}{2} mv^2$
• D. $F \cdot 5$

Hint:

For constant force, the work done can be calculated by multiplying the force by the displacement.

Answer 1

The Correct Option is A

The work done by a constant force $F$ is given by the formula: $$W = F \cdot d,$$ where $d$ is the displacement of the block. 
If the block is moving with velocity $v$, after time $t = 5$ seconds, the displacement will be $d = v \cdot 5$. Thus, the work done is: $$W = F \cdot (5v) = Fv.$$