It takes 40 J of energy to push a large box 4m across a floor. Assuming the push is the same direction as the movement, what is the magnitude of the force of the box?

10 N

Explanation:

Work done is the dot product of the force magnitude with distance and cosine of the angle betweenthem.

Equation to use: W=|F|*|d|*cosθ

Your unknown is the force F; You have one equation, oneunknown.

40j=(F)*(4m)*cos(0)

F=40j/4m

F=10N

a small object of mass 3.66 g and charge -17.6 µc is suspended motionless above the ground when immersed in a uniform electric field perpendicular to the ground. what are the magnitude and direction of the electric field?

measure their densities same density, same sub