A garage door opener has a power rating of 350 watts. If the door is in operation for 30 seconds, how many joules of energy are used? (Hint: Remember that 1 watt = 1 joule/sec)

How may substance be tested to determine whether or not it is an element?

What kind of wave is sound and how do the particles move?

As a car comes to a skidding stop, what happens to the car's energy 1. Gravitational potential energy increases. 2. Gravitational Potential energy decreases 3. Internal energy decreases. 4. Internal energy increases

When is the potential energy of a pendulum at its greatest?

Walt ran 5 km in 25 minutes going east to what was his average velocity

An example of a stable system

What causes chemical weathering? a. damage caused by animals and plants c. natural acids b. ice wedging d. physical factors

1. Strzała o masie 20 g tuż po wystrzale ma prędkość 50 m/s. Oblicz pracę wykonaną przez zawodniczkę. Ile wynosi energia potencjalna sprężystości napiętej cięciwy? 2. Na trampolinę o współczynniku sprężystości k=2 kN/m stanął zawodnik o masie 80 kg.

Two small plastic spheres between them has magnitude 0.22 N. What is the charge on each sphere is one the other? Explain whether it can be determined from the information give, whether the charges are positive or negative.

If it has enough kinetic energy, a moleculeat the surface of the Earth can escape the Earth's gravitation. The acceleration of gravity is 9.8 m/s2, and the Boltzmanns' constant is 1.38066*10-23 J/K.