A cart that has a mass of 56 kg is being pushed down the road at an acceleration of 12 m/s2. The force of friction on the cart is 3 N. What is the net force acting upon the cart? (hint: net force is the sum of all forces Fa + Ff)

The electric field between square plates of a parallel-plate capacitor has magnitude e. the potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. the magnitude of the electric field between the plates is now equal to a)e b)e/4 c)e/2 d)4e e)2e