Which statements correctly compare the gravitational force with the electrical force?

a. the gravitational force can be repulsive.
b. the gravitational force can be attractive.
c. the electrical force can be repulsive.
d. the electrical force can be attractive.
e. any two objects experience a gravitational force between them.
f. any two objects experience an electrical force between them.

Immediately upon reaching its lowest point, a falling pendulum bob has its greatest amount of energy, which is the initial amount of potential energy. a. heat; less than b. heat; more than c. kinetic; less than d. kinetic; more than

If you put a helium-filled balloon in the refrigerator, what will happen?

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.