Question

A block of mass M is pulled over a distance D by an applied force F which is directed in parallel to the displacement.how much work is done on the block by the force F ?

Answer 1

the force applied on the couches FBA.

Answer 2

Answer:

The work done by the force on the block = FD.

Explanation:

The work done by a uniform force on an object is equal to the dot product of the applied force $\vec F$ and the displacement $\vec d$ covered by the object.

$\text{Work done,}\ W=\vec F \cdot \vec d$

If the applied force is not uniform but varies with the distance, then the work done by the force in displacing the object by some displacement $\vec d$ is given by

$W=\int\limits^d_0 \vec F\cdot d\vec x$.

Given that a block of mass M is pulled over a distance D by an applied force F which is directed in parallel to the displacement.

Since the applied force $\vec F$ is parallel to the direction of displacement $\vec D$, therefore, the angle $\theta$ between the force and the displacement is $0^\circ$.

Thus, the work done by force on the block is given by

$W=\vec F \cdot \vec D\\ = |\vec F||\vec D|\cos\theta \\=FD\cos(0^\circ)\\=FD.$