Physics Question?

Question

Mark is pulling a 12kg cart at a constant acceleration of 1.5 m/s^2 along a horizontal floor with a downward force of 20N, 20° below the horizontal.

a. What is the magnitude of the frictional force that the cart is experiencing if the coefficient of friction between the cart and the floor is 0.2?

b. What is the acceleration of the cart?

Answer 1

Strange that this question seems to have too much information...

I'll give it a go anyway:

the normal force is:
20*sin(20)+12*9.81
=124.6 N

Using the .2 coefficient
Friction=24.9N

Which means that Cos(20)*20
is insufficient for a positive acceleration
so I will ignore the constant acceleration

and compute (b) as
F=m*a
20*cos(20)-24.9=12*a
a=(20*cos(20)-24.9)/12
= -.5 m/s^2


j