# Dynamics Wagon Problem

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1. Mar 28, 2016

### IbrahimA

1. The problem statement, all variables and given/known data
A child is pulling a wagon of mass 7.38 kg up a hill inclined at an angle of 14.3 degrees to the horizontal. The child applies a force parallel to the hill. The acceleration of the wagon is 6.45 cm/s^2 up the hill. Friction is negligible. Determine the magnitude of (a) the force applied by the child, and (b) the normal force on the wagon.

FBD Diagram I drew:

(a) 18.3 N
(b) 70.1 N

2. Relevant equations
Fnet = ma

(a) Fnet = -Fgx + Fa
(b) Fn = -Fgy

3. The attempt at a solution
(a)
Fnet = (-Fgx) + Fa
ma = m(-g)(cos14.3) + Fa
(7.38)(0.0645) = (7.38)(-9.8)(cos14.3) + Fa
71.9 N = Fa

(b)
Fn = Fgy
Fn = (7.38)(-9.8)(cos14.3)
Fn = 11.7 N

2. Mar 28, 2016

### TSny

Welcome to PF!

Note that you've used the cosine function for getting both Fgx and Fgy.

Make sure your calculator is in "degree mode".

3. Mar 28, 2016

### IbrahimA

I literally just checked it now, its was on radians. I redid the calculations and they are correct.
Thank you so much.

4. Mar 28, 2016

Good work!