physics question

Question

A rightward force is applied to a crate to push it across the floor at a constant speed. Ignore air resistance.

The applied force is 6.80 N.

The crate is 10 kg.

What is the value of the opposing frictional force?

What is the acceleration of the crate

What is the weight of the crate?

What is the normal force on the crate?

Answer 1

What is the normal force on the crate?

Since the crate does not move up or down the normal acceleration is zero. Therefore, by the 2nd Newton law the normal force is zero. There are two normal forces, the weight directed down and the reaction of the surface directed up. They have the same value, but opposite direction and thus their sum is zero.

Answer 2

A rightward force is applied to a crate to push it across the floor at a constant speed. Ignore air resistance.

The applied force is 6.80 N.

The crate is 10 kg.

What is the value of the opposing frictional force?

Since the velocity is constant, the crate is in dynamic equilibrium. This implies zero net force.

Because the rightward force is 6.80N, we have

Force_Net = rightward force - frictional force

0 = 6.80+( - frictional force)

Therefore, frictional force is 6.80N acting to the left

What is the acceleration of the crate

Since net force is zero, acceleration is also zero.

What is the weight of the crate?

W = m•g

W = 10•9.81 = 9.81N (10N correct to 1 significant digit)

What is the normal force on the crate?

since the surface is horizontal, normal Force = weight = 10N

Mr, A