Question

A crate with a mass of 1000 kg is being pulled along greased tracks by a winch. The winch is exerting a force of 2000 N

in the horizontal direction along the tracks. The coefficient of kinetic friction between the crate and the tracks is 0.2.

20. What is the net force acting on the crate in the horizontal direction?

21.
Using Newton's second law, calculate the crate's acceleration.

Answer 1

We are given:

Coefficient of Kinetic Friction = 0.2

Mass of the crate = 1000 kg

Force applied = 2000 N

Net force Acting on the crate in the Horizontal Direction:

Normal Force applied on the Crate:

Normal force is the force applied on the object by the surface. It is equal and opposite to the force of gravity

So, we can say that Normal force = | Gravitational Force |

Normal Force = | mg |

Normal Force = 1000 * 9.8

Normal Force = 9800 N

Finding the Frictional Force:

We know that:

coefficient of Kinetic friction = Friction force / Normal force

replacing the known values

0.2 = Friction force / 9800

Friction Force= 0.2 * 9800

Friction Force = 1960 N

Net force acting on the Crate:

We know that a force of 2000 N is being applied on the crate in the Horizontal direction

Frictional force is always opposite to the horizontal force. So, we can say that:

Applied force - Friction Force = Net Force

replacing the variables

2000 - 1960 = Net force

Net Force = 40N

Therefore, a net force of 40N is being applied on the Crate

Acceleration of the Crate:

From newton's second law of motion:

F = ma

replacing the variables

40 = 1000 * a

a = 40/1000

a = 0.04 m/s²

Hence, the crate will have an acceleration of 0.04 m/s²