A clumsy astronaut falls into a crater on the moon. The crater is 13 meters deep. How long will the astronaut have before he hits the ground?

The acceleration due to gravity at the surface of a planet depends on the planet's mass and size; therefore other planets will have accelerations due to gravity different from 9.8 m/s2.

Does the eruption in the video constitute a pyroclastic flow

A passing warm front changes air pressure. does a passing warm front increase or decrease air pressure

Which factors that affect the Florida peninsula can result from human activity? A. the formation of sand dunes and springs B. the formation of springs and drilling of artesian wells C. the intrusion of salt water and formation of sand dunes D.

Which of these is a benefit of fuel cell cars? Fuel cell cars reduce the use of fossil fuels. Hydrogen fuel is volatile. Fuel cell cars are quickly recharged. Hydrogen fuel is a limited resource.

In a recent hockey game, one player (m=100kg) was moving at a velocity of 8 m/s when he ran into another player (m=300kg) who was at rest (v=0m/s). After the collision, the two players were stuck together (moving with the same velocity).

In a laser, electrical energy is changed to light energy, and a small amount of the energy is wasted as heat. Describe the total amount of the heat in the system (using the conservation of energy).

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.