Question

An object of mass m = 20 kg is pushed with a force F = 40 N parallel to a rough horizontal surface with a coefficient of kinetic friction μ_k=0.1.The  acceleration of the object is equal to:

Answer 1

Step-by-step explanation:

For the object to move, it must overcome the frictional force.

Thus,

Net force = Pushing force - frictional force

From the information given,

Pushing force = F = 40 N

Frictional force = normal reaction x coefficient of kinetic friction, μ

μ = 0.1

Normal reaction is equal and opposite to the weight. Thus,

normal reaction = mg

where

m is the mass of the object

g is the acceleration due to gravity and its value is 9.8 m/s^2

Thus,

normal reaction = 20 x 9.8 = 196 N

Frictional force = 196 x 0.1 = 19.6

Thus,

Net force = 40 - 19.6 = 20.4

Recall,

Net force = mass x acceleration

acceleration = Net force/mass

acceleration = 20,4/20 = 1.02

By rounding to the nearest whole number,

acceleration = 1 m/s^2