Question

Determine the appropriate coefficient of friction in each case.
a) It takes 59 N of horizontal force to get a 22kg leather suitcase just starting to move across the floor.
b) A horizontal force of 54 N keeps the suitcase moving at a constant velocity.

Answer 1

To determine the coefficient of friction in both cases, we can use the equation:

Frictional force = coefficient of friction * normal force

a) In this case, the horizontal force required to get the suitcase just starting to move is 59 N. The normal force acting on the suitcase is equal to its weight, which is given by:

Weight = mass * gravity
= 22 kg * 9.8 m/s^2
= 215.6 N

Using the equation for frictional force, we have:

59 N = coefficient of friction * 215.6 N

Solving for the coefficient of friction:

coefficient of friction = 59 N / 215.6 N ≈ 0.273

b) In this case, the horizontal force required to keep the suitcase moving at a constant velocity is 54 N. The normal force acting on the suitcase is still equal to its weight, which is 215.6 N.

Using the equation for frictional force, we have:

54 N = coefficient of friction * 215.6 N

Solving for the coefficient of friction:

coefficient of friction = 54 N / 215.6 N ≈ 0.25

Therefore, the appropriate coefficient of friction in case (a) is approximately 0.273, and in case (b) it is approximately 0.25.