Question

A person pushes a refrigerator across a horizontal floor. The mass of the refrigerator is 110 kg, the coefficient of static friction between the refrigerator and the floor is 0.85, and the coefficient of kinetic friction between the refrigerator and the floor is 0.59.
(a) If the refrigerator is initially at rest, determine the minimum magnitude of the force that the person must exert horizontally on the refrigerator to cause it to move.
N

(b) Once the refrigerator is moving, determine the magnitude of the force that the person must exert horizontally on the refrigerator to keep it moving at a constant speed.
N

(c) Determine the acceleration of the refrigerator if the person applies a horizontal force of magnitude 950 N on the refrigerator.

Answer 1

Answer:

Explanation:

mass of refrigerator, m = 110 kg

coefficient of static friction, μs = 0.85

coefficient of kinetic friction, μk = 0.59

(a) the minimum force required to just start the motion in refrigerator

F = μs x mg

F = 0.85 x 110 x 9.8

F = 916.3 N

(b) The force required to move the refrigerator with constant speed

F' = μk x mg

F' = 0.59 x 110 x 9.8

F' = 636.02 N

(c) Let a be the acceleration.

Net force = Applied force - friction force

F net = 950 - 636.02

F net = 313.98 N

a = F net / mass

a = 313.98 / 110

a = 2.85 m/s²