Q. A small object with a mass of 380 mg carries a charge of 40.0 nC and is suspended by a thread between the vertical plates of a parallel-plate capacitor. The plates are separated by 4.00 cm. If the thread makes an angle of 18.0° with the vertical, what is the potential difference between the plates?
Q. A player uses a hockey stick to push a puck at a constant velocity across the ice. The weight of the puck is 1.70 N. The coefficient of friction is 0.0600. With what force must the player push the puck so that his force just equals the frictional force?