Question

Suppose you put a wooden block flat against a wood wall and

pushed horizontally with a force of 200 N (which is the minimum force
required to keep it from falling).
(a) Draw a ""free-body"" diagram showing all the forces acting on the block and the causes of these forces.
(b) What is the magnitude of the normal force?
(c) What is the force of fricticn?
(d) What is the weight of the object? The mass?
(e) If a constant force of 120 N is applied, at what rate wll the block accelerate down the wall?

Answer 1

(a) The free body diagram consists of weight, normal force of the block and force of friction.

(b) The normal force of the wooden block is 200 N.

(c) The force of friction is 200 N.

(d) The weight of the wooden block and its mass is 200 N and 20.41 kg respectively.

(e) The acceleration of the block at the applied force is 5.88 m/s².

How to calculate the magnitude of the normal?

(b) The normal force of the wooden block is calculated by applying Newton's third law of motion;

action = reaction

N = 200 N

(c) The force of friction is calculated by applying Newton's second law of motion

F(net) = ma

F - Fs = 0

F = Fs

Fs = 200 N

(d) The weight of the wooden block and its mass is calculated as;

N = W

W = 200 N

W = mg

m = W / g

m = ( 200 N ) / ( 9.8 m/s² )

m = 20.41 kg

(e) The acceleration of the block at the applied force is calculated as;

F(net) = ma

a = F(net) / m

a = ( 120 N ) / 20.41 kg

a = 5.88 m/s²