Why do scientists believe that dark matter exists even though it cannot be seen?

Give an example of an energy conversion that produces an unwanted form of energy?

If a glass rod is rubbed with a dry cloth, what kind of charge would it be: A) positive, due to extra protons B) negative, due to protons lost C) positive due to electrons lost D) negative, due to extra electrons

What is the period that corresponds to afrequency of 83.3 hz? answer in units of s?

What did Galileo discover when he dropped two cannon balls of different weights from the Leaning Tower of Pisa?

2. when sugar or another substance is dissolved in water, it disappears from view and forms a homogeneous mixture with the water, also called a solution. if you can't see the sugar, how can you tell that it is there?

What two things change when an object is travelling at a constant speed

Two people are standing on a 3.12-m-long platform, one at each end. The platform floats parallel to the ground on a cushion of air, like a hovercraft. The two people, the platform and a 3.36-kg ball are all initially at rest. One person throws the 3.

Compared with falling on a wooden floor, a wine glass may not break when it falls to a carpeted floor because of the

Explain the formation of color in terms of reflection and absorption of light waves.

Stretched 1 cm beyond its natural length, a rubber band exerts a restoring force of magnitude 2 newtons.