A boy is pushing a 80 kg box along the floor. The force is exerted at the top of the box with an -30 degree angle with respect to the horizon. The kinetic friction is 0.40, and g is 9.8m/s^2.(adsbygoogle = window.adsbygoogle || []).push({});

Find the force needed to keep the box moving with a constant velocity.

80kg = 784 N

Force needed to keep it moving: 784*0.40= 313.6 N

Since we want constant velocity, the kinetic forces and the applied forces need to be in equilibrium.

313.6N = mg*sin 30 + mg*cos30

313.6N - (mg*sin 30 + m*cos 30) = 0

Is this correct?

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# Homework Help: Boy pushing box along floor - friction

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