Here you see the blade that cuts and mulches vegetation by whirling at high speed. What type of simple machine is the blade?

If 1 lb of fat is stored by the body for each 14.6×103kj of excess nutritional energy consumed, how long will it take this person to gain 1 lb?

What happens to the velocity of the car when the upward pull of the cable is greater than the downward pull of gravity as the car rises toward the top?

Explain to someone who knows nothing about fossils the study of invertebrate paleontology and how it scientists understand the history of the earth. be sure your explanation contains a minimum of two complete sentences.