A 20 kg crate of books is at rest on a table. what is the normal force on the books?

What does the doppler effect tell astronomers about the universe

How to change the amount of charge to increase the current

Two identical billiard balls are rolling toward each other at the same speed. What will be true after they collide head-on?

A 4000 kg elevator rises from the basement to the top of a100-m tall building. Which of the following is closest to the network done on the elevator as it rises through the middle 20m of itstrip at a constant velocity? Use g=10m/s^2. A.) 800,000 J B.

A 2.3-kg object traveling at 6.1 m/s collides head-on with a 3.5-kg object traveling in the opposite direction at 4.8 m/s. if the collision is perfectly elastic, what is the final speed of the 2.3-kg object?

When you bring the negatively charged balloon near a rod, how do the electrons move? The electrons move away from the balloon. The electrons do not move. The electrons move toward the balloon.

Mazie stands on her kitchen floor. The coefficient of kinetic friction between her socks and the floor is 0.62, and the coefficient of static friction is 0.75. She has a mass of 42 kg. a.

The kinetic energy of an object is quadrupled. its momentum will change by what factor?

Combining which of the following substances with germanium will cause the germanium to emit free electrons? A. Bismuth B. Gallium C. Aluminum D. Indium

A 50.0-g Super Ball traveling at 25.0 m/s bounces off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.