A train is 240 meters long and travels 20 m/s. How long does

it take to cross a 360-meter long bridge?

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What is the coldest place on earth

According to the equation for the Balmer line spectrum of hydrogen, a value of n = 3 gives a red spectral line at 656.3 nm, a value of n = 4 gives a green line at 486.1 nm, and a value of n = 5 gives a blue line at 434.0 nm.

The density of a material is calculated by:

An aerobatic airplane pilot experiences weightlessness as she passes over the top of a loop-the-loop maneuver. The acceleration of gravity is 9.8 m/s^2 If her speed is 440 m/s at this time, find the radius of the loop. Answer in units of km.

Energy which travels through space in the form of waves is known as

Imagine two artificial satellites orbiting earth at the same distance. one satellite has a greater mass then the other one which of the following would be true about there motion? 1.

What is energy? (Not the answer from google search.)

Explain why the friction force between two surfaces increases if the force is pushing the surfaces together increases.

As energy moves in waves through the water, the water moves a. in waves toward shore. c. in the direction of the waves. b. in a small circular movement. d. against the current.

Which of the following values represents an index of refraction of an actual material? A. 0 B. 1 / 4 C. 5 / 4 D. 1 / 2