A 9 kg box is moving at a constant speed of 6 m/s to the right of a table. It experiences a leftward force of 13 N and an unknown rightward force.

A. Draw a force diagram describing this situation. Please label all forces.

B. Determine the magnitude of the unknown rightward force. Explain how you know.

I'm getting confused on what equations to use in order to solve for magnitude and other forces, do I also have to use the Kinematic Equations? Or is that only if I'm solving for time, acceleration, etc.

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put on hold as off-topic by Dale, rob Dec 9 at 0:29

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  • If the net force is zero than nothing will change. If you have a net force or are given an acceleration ( like we use for gravity on earth which is a force (proportional to mass) that results in the same acceleration for every mass) then you can start doing kinematics. – PhysicsDave Dec 9 at 3:39

We know that if a particle is moving with constant velocity, it has no acceleration. Thus you know that there is a rightward force of 13N applied to the box.

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