- #1

- 62

- 0

Question:

In many neighborhoods, you might see parents pulling youngsters in a four-wheeled wagon. The child and the wagon have a combined mass of 50 kg and the adult does 2.2 x 10^3 J of work pulling the two 60 m at a constant speed. The coefficient of friction for the surfaces in contact is 0.26.

a) Determine the magnitude of the force applied.

b) Determine the angle at which the parent is applying this force.

My answer:

a)

Fapp = Ff + Fg

= uFn + Fg

=u(mg) + mg

=(0.26)(50 kg)(9.8N/kg) + (50 kg)(9.8 N/kg)

=617.4 N

Therefore the force that the parent applies to the wagon is 617.4 N

b) W = Fapp x cos(theta) x (delta)d

cos(theta) = W / (Fapp(delta)d)

= (2.2 x 10^3 J) / (617.4 x 60 m)

theta = 87 degrees

Therefore the parent is applying this force at 87 degrees to the horizontal.

Thanks in advance!