If element X has 21 protons, How many electrons does it have?

Caves most commonly form in which rock type

A 24 kg child on a 3.2 kg sled is sliding at 6.0 m/s. as the sled passes underneath a tree, a 5.2 kg mass of snow falls vertically and lands on the moving sled. calculate the final velocity of the sled.

What does the number, or density, of field lines on a source charge indicate? A. direction of charge on the source charge B. amount of charge on the test charge C. amount of charge on the source charge D. direction of charge on the test charge

A microwave oven with a power of 1.4 kW is used for 0.10 hours. How much electricity did the power company provide for the microwave?

Imagine a bouncing ball that does not lose any energy

Scientists who study races and their origins are called A. anthropologists. B. ethnologists. C. paleontologists. D. sociologists.

Why are telescopes that detect non - optical radiation useful for studying objects in space

Which of the following is not an application of Doppler technology? police speed guns weather radar ultrasound imaging of the liver determining the motion of a star

For a constant voltage, increasing the resistance will cause the current to decrease. true or false

Which of the following is an example of a testable scientific hypothesis? A) Why do plants grow better in the Sun than in the shade? B) Peacocks have prettier tail feathers than pigeons do.