Question

A man is trying to drag a small tree that he cut down. If the static coefficient

of friction of the tree on the ground is 0.5 and the tree weighs 480 N, what is
the minimum amount of horizontal force that the man will need to apply so
that the tree will start moving?

A. 240 N
B. 360 N
C. 480 N
D. 120 N

Answer 1

120 N

Explanation: First we shoud consider the forces acted on a tree

Friction foce - acting opposite to the moving direction

Weight - Directly acting downwards

Reaction - Directly acting on upwards

For minimum required force should be equal to the friction force

F = μ R

F = 0.5×480

= 120N