Answer:
300 J
Explanation:
First of all, we need to calculate the net force acting on the crate, which is given by:
[tex]F_{net} = F-F_f[/tex]
where
F = 100 N is the horizontal push
[tex]F_f = 70 N[/tex] is the force of friction
Substituting,
[tex]F_{net}=100 - 70 = 30 N[/tex]
Now we can calculate the net work done on the crate:
[tex]W=F_{net}d[/tex]
where
d = 10 m is the displacement
Substituting,
[tex]W=(30)(10)=300 J[/tex]
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.
