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: \[ W = F \cdot (5v) = Fv. \]