Question

how much work is done by a person if he pulls a crate with a force of 250 N at an angle of 60 and crate moves 20 m
if the same amount of force is applied horizontally, how much work is done if the crate still move the same distance ?

Answer 1

QUESTION:

How much work is done by a person if he pulls a crate with a force of 250 N at an angle of 60 and crate moves 20 m if the same amount of force is applied horizontally, how much work is done if the crate still move the same distance?

ANSWER

The work done by a constant force of magnitude $F$ on a crate that moves a distance $d$ in the direction of the force is:

$$W = F d \cos \alpha$$

$\alpha$ is the angle between $\vec{F}$ and $\vec{d}$.

Hence in the first case the work done is

$$W = F d \cos \left(60{}^{\circ}\right)$$ $$W = 250 \cdot 20 \cdot 0.5 = 2500 \text{ J}$$

And in the second case work is

$$W = 250 \cdot 20 \cdot \cos (0{}^{\circ}) = 250 \cdot 20 \cdot 1 = 5000 \text{ J}$$

ANSWER

2500 J and 5000 J