Question

A 20-kg wagon accelerates on a horizontal surface at 0.50 m⁄s2 when pulled by a rope exerting a 120-N force on the wagon at an angle of 25° above the horizontal. Determine the magnitude of the effective friction force exerted on the wagon and the effective coefficient of friction associated with this force.

Answer 1

Answer:

Explanation:

given,

mass of wagon = 20 Kg

horizontal acceleration = 0.5 m/s²

force of pull = 120 N

angle with horizontal = 25°

Applying newtons second law

F cos θ - f = m a

f = F cos θ- ma

f = 120 cos 25° - 20 x 0.5

f = 99 N

we know,

f = μ N

μ =$\dfrac{f}{N}$

μ =$\dfrac{99}{mg - Fsin \theta}$

μ =$\dfrac{99}{20\times 9.8 - 120 sin 25^0}$

μ = 0.68