Answer:
50 N
Explanation:
The minimum horizontal force required to start the crate moving must be equal to the maximum force of static friction that acts between the floor and the crate.
The maximum force of static friction is given by:
[tex]F_f = \mu N[/tex]
where
[tex]\mu[/tex] is the coefficient of static friction
[tex]N[/tex] is the normal reaction exerted by the floor on the crate.
For wood-wood, as in this case, the maximum coefficient of static friction is about [tex]\mu=0.5[/tex].
For a horizontal surface, the normal reaction is equal to the weight of the object, so in this case [tex]N=100 N[/tex]. Therefore, the minimum horizontal force required will be:
[tex]F=F_f = \mu N=(0.5)(100 N)=50 N[/tex]
