two of your neighbor's children (40kg together) sit on a sled. You push the back child with a 50-N force directed 37 degrees below the horizontal plane. The sled slides forward at constant velocity. How would i solve for the normal force the surface exerts on the sled?

Question

a_clan · Answer

the normal force exerted by the surface on the sled = weight of sled(along with boys) + component of force in the perpendicularly downward direction

anonymous · Answer

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If I understadnd the question correctly, then we need to find sum of the foreces in the y-component to find the Normal force. My assumption is that we can treat the sled+children together as one system.
$$\Sigma F _{y}=0$$ Since the sled only moves horizontally and has no acceleration in the y-direction.
Therefore; $$N _{f}-mg+50Nsin(37)=0$$
$$N_{f}=40(9.81)N+30.09075N=422.5N$$

Let us know whether or not this is correct.