Question

If you push a crate horizontally with 100 N across a 10 m factory floor and the friction between the crate and the floor is a steady 70 N, how much kinetic energy does the crate gain?

Answer 1

Answer:

300 J

Explanation:

First of all, we need to calculate the net force acting on the crate, which is given by:

$F_{net} = F-F_f$

where

F = 100 N is the horizontal push

$F_f = 70 N$ is the force of friction

Substituting,

$F_{net}=100 - 70 = 30 N$

Now we can calculate the net work done on the crate:

$W=F_{net}d$

where

d = 10 m is the displacement

Substituting,

$W=(30)(10)=300 J$

According to the work-energy theorem, the kinetic energy gained by the crate is equal to the work done on it: therefore, the answer is 300 J.