A boy drops a 0.10 kg stone down a 150 m well and listens for the echo. The air temperature is 20°C. How long after the stone is dropped will the boy hear the echo? The speed of sound through air at 20°C is v = 343 m/s.

A wave oscillates 5.0 times a second and has a speed of 4.0m/s what is the frequency of this wave

The energy of motion is called A. kinetic energy. B. potential energy. C. thermal energy. D. work.

The man jumps from the window of a burning hotel and lands in a safety net that stops him fall in 1 mm. Determine the average force that the net exerts on the man if he enters the net at a speed of 28 m/sm/s. Assume that the man's mass is 64 kgkg.

What is one property that all particles of matter have in common?

What causes more friction, wax paper, aluminum foil, or plastic wrap

Magma appears to be rising underneath the mid-oceanic ridges. a. True b. False

The energy required to crack a material

two punds of water vapor at 30 psia fill the 4ft3 left chmaber of a partitioned system. The right chmaber has twice the volume of the left and is initially evacuated.

Why do we eat today

Which statement about ammeters and voltmeters is true? A. Current and voltage are the same throughout a circuit so where you place the ammeter and voltmeter doesn't matter. B.