How many neutrons does element X have if it's atomic number is 21 and it's mass number is 75

A 2000 kg car is moving at 15 m/sec when it collides with a 1200 kg car sitting still. Briefly compare the impulse imparted on the 1200 kg car by the 2000 kg car to the impulse imparted on the 2000 kg car by the 1200 kg car.

After precipitation falls, the water moves into the lithosphere through openings in the rock or soil. What is this process called?

A race car travels on a circular track at an average rate of 125 mi/h. The radius of the track is 0.320 miles. What is the centripetal acceleration of the car?

How is an electromagnet different from a bar magnet? A) Bar magnets have a north and south pole, but electromagnets do not. Eliminate B) Electromagnets are strong, permanent magnets, but bar magnets are always weaker.

A bike travels at a constant speed for 4.00 m/s for 5.00 seconds. How far does it go

Since 1 pound = 4.45 newton, what is your earth weight in newtons?

A girl moves at 2m/s delivering newspapers. she throws a newspaper directly behind her at 2m/s. in the frame of reference of someone standing nearby what is the motion of the newspaper.

What forces are acting on matter through contact or no contact

Consider the following when writing your report: a) Start by making a rough plan for how you will solve the problem. In particular, divide the big problem into two or more smaller problems that each involves one basic physics idea.

Two children are bouncing small rubber balls. One child simply drops a ball. At the same time, the second child throws a ball downward so that it has an initial speed of 10 m/s. What is the acceleration of each ball while in motion?