A plastic ball with a charge of +1.0 C is brought near another ball with a charge of --2.0 C. The balls are let go so that they are free to move. What happens?
The negatively charged ball does not move, but the positively charged ball starts
to move toward it because of an attractive force.
The balls move apart because they exert equal repulsive forces on each other.
Nothing. Both balls stay exactly where they are.
The balls both start moving toward each other because they exert equal
attractive forces on each other.

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

Amass attached to a spring is displaced from its equilibrium position by 5cm and released. the system then oscillates in simple harmonic motion with a period of 1s. if that same mass–spring system is displaced from equilibrium by 10cm instead, what will its period be in this case? a mass attached to a spring is displaced from its equilibrium position by and released. the system then oscillates in simple harmonic motion with a period of . if that same mass–spring system is displaced from equilibrium by instead, what will its period be in this case? a) 0.5sb) 2sc) 1sd) 1.4s

Explain why you think this diagram shows what happened to the carbon in the biodome.