Which colors will eject electrons when they strike sodium, which has a frequency threshold of 5.7 * 1014 Hz?

What is the central equation of mass-energy equivalence?

Kevin jumps straight up in the air to a height of 1 meter. At the top of his jump, he has potential energy of 1,000 joules. Answer the following question based On these answers. What is Kevin's weight? a. 200 Newtons b. 1,000 Newtons c.

A stone is tied to s string and whirled around in a circle at constant speed. Is the string more likely to break when the circle is horizontal or when it is vertical? Account for your answer, assuming the constant speed is the same.

An elevator weighs 1500 Newtons. Calculate how much potential energy it has when it is lived 500 meters in the air. 75,000 J 750 J 7,500,000 J 750,000 J

As a substance changes phase from solid to liquid to gas, the molecules become closer together.

Which of the following is not shorthand to describe one of the three types of ecological relationships? +/+ -/+ +/0 -/0

Which is a characteristic of an electromagnetic wave?

What does the ozone layer absorb? a. Microwaves c. UV radiation b. X-rays d. Infra-red radiation

An object is undergoing shm with period 0.900 s and amplitude 0.320 m. at t = 0 the object is at x = 0.320 m and is instantaneously at rest. calculate the time it takes the object to go (a) from x = 0.320 m to x = 0.160 m and (b) from x = 0.

Your friend states in a report that the average time required to circle a 1.0-mi track was 49.325 s. This was measured by timing 10 laps using a stopwatch with a precision of 0.01 s. Do you believe his results are reliable? Explain.