Which two energy sources together provide more than 50% of the energy needs of the United States?

Let's say a 0.001kg bullet moves with a speed of 1500 m/s. A pitcher claims he can throw a 0.15 kg baseball with as much momentum as that bullet. How fast would he have to throw the ball for this to be true?

What is wave diffraction? A. absorbing of a wave B. traveling through the medium C. bending of the wave D. bouncing off of the wave

Life-form that existed during the paleozic era included

A commuter train blows its 200-Hz horn as it approaches a crossing. The speed of sound is 335 m/s. An observer waiting at the crossing receives a frequency of 207 Hz. What is the speed of the train?

Double bonds can only exist when both atoms being bonded together are the same type of element.* True False

Which of the following subatomic particles does not have a charge? A.) electron B.) proton C.) neutron D.) positron

How do we use light in space?

What units are used for gravitational potential energy? Write the name, not the symbol.

A 7.5 kg block is placed on a table. If it's bottom surface area is 0.6m2, how much pressure does the block exert on the tabletop? A. 376.5 Pa B. 73.5 Pa C. 226.5 Pa D. 122.5 Pa

A boulder of mass 2000 kg is at the top of a cliff of height 220 m. Determine how fast the boulder will be moving when it strikes the dirt below.