What are two disadvantages of burning coal, oil, or natural gas to provide energy?

A car travels 400 km in 5 hours. what is the average speed of the car (in km/hr) ?

A bicyclist is in a 50-km race. He says he had an average velocity of 35. What is missing in the cyclist's velocity? A. units only B. units and distance C. direction only D. units and direction

Two astronauts, one of mass 60 kg and the other 90 kg, are initially at rest together in outer space. they then push each other apart. how far apart are they when the lighter astronaut has moved 15 m?

If an object is moving with a constant acceleration, then it could NOT be OA) changing its direction OB) moving in a straight line OC) moving at a constant speed OD) moving at a constant velocity

In this case, lithium would be classified as a (n) A) atom. B) compound. C) ion. D) molecule.

Which of Newton's laws, when combined algebraically with his law of universal gravitation, can be used to calculate Earth's mass? A) first B) second C) third

Why does a balloon filled with helium rise while a balloon filled with an equal volume of average atmospheric air does not? A. Helium has no mass, but air does. B. Helium increases the balloon's mass more than air. C.

Consider the following controls in an automobile in motion : gas pedal, brake, steering wheel. what are the controls in this list that cause an acceleration of the car?

What material are oil pipelines made from?

3/129 A 175-lb pole vaulter carrying a uniform 16-ft, 10-lb pole approaches the jump with a velocity v and manages to barely clear the bar set at a height of 18 ft. As he clears the bar, his velocity and that of the pole are essentially zero.