20. The model of the universe that suggests that the sun is the center of the universe was first brought by

A. Copernicus.

B. Brahe.

C. Ptolemy.

D. Kepler.

Why is plastic and foam a good material for ear defenders?

Which of the following is not an example of work? a. raising a barbell over your head b. picking up a box off the floor c. holding a tray in the cafeteria line d. pushing a box across the floor

When two carts having the same mass and the same speed collide and bounce off of each other elastically, what is the final momentum of the carts?

A box of cleaning supplies weighs 15 n. If the box is lifted a distance of. 60 m, how much work is done?

You can only change one variable in an experiment true or false

What is the name for a star and planets held together by gravity? A. solar system B. galaxy C. black hole D. supernova

When a car turns a corner on a level road, which force provides the necessary centripetal acceleration? 1) gravity 2) normal force 3) air resistance 4) tension 5) friction

Use Newton's universal law of gravitation to explain why gravity is greater on Earth than on Mercury.

What is a magnetic field and how does it interact with magnetic materials?

What is significant about holden sitting on the radiator?