How do scientists know the Earth's magnetic field has reversed itself many times in the past?

The frequencies of visible light are the highest frequencies on the electromagnetic spectrum. True False

1. The matter a wave travels through is called a

A mule pulls a cart of milk 10 meters with a force of 50 Newton's. Calculate the work done by a mule

Radiation form ions by removing protons from matter as it passes through. What's it called?

Mutt and Jeff are running along a path each pushing a cart loaded with rocks. If Mutt's wagon has a mass two times greater than Jeff's and they want to stay together, arriving at their destination at the same time, what must happen?

8. A force of 80 pounds on a rope is used to pull a box up a ramp inclined at 100 from the horizontal. The rope forms an angle of 330 with the horizontal. How much work is done pulling the box 25 feet along the ramp?

A raindrop has a mass of 5.4 * 10-7 kg and is falling near the surface of the earth. Calculate the magnitude of the gravitational force exerted (a) on the raindrop by the earth and (b) on the earth by the raindrop.

As an astronaut travels towards Earth, her weight A. decreases because gravity decreases. B. decreases because her mass decreases. C. increases because gravity increases. D. remains the same because her mass remains the same.

Lightning often strikes water. a. True b. False

How much work must be done on a 10 kg snowboard to increase its speed from 4 m/s to 6 m/s?