What are the forces acting on a child pulling a wagon up an inclined hill?

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IbrahimA
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Homework Statement


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:
hShKWw8.jpg


Correct Answers on book:
(a) 18.3 N
(b) 70.1 N

Homework Equations


Fnet = ma

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

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


 
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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".
 
TSny said:
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".

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