Grinding quartz crystals down to produce sand is an example of a

a.

change of state.

c.

chemical reaction.

b.

chemical change.

d.

physical change.

Astronauts in orbit are not truly weightless.

Compare and contrast the properties of visible light ultraviolet rays and x-rays

A particular wire has a resistivity of 6.47*10-8 Ωm and a cross-sectional area of 2.32 mm2. A length of this wire is to be used as a resistor that will develop 130 W of power when connected to a 9.00 V battery. What length of wire is required?

As energy transformations occur within a system, the total energy of the system it A) increases B) decreases C) remains constant D) is transferred out of the system 2

Two bowling balls each have a mass of 8 kg. If they are 2 m apart, what is the gravitational force between them? G = 6.67 * 10^-11 N⋅ (m/kg) ^2 A. 3.21 10^-8 N B. 2.14 10^-9 N C. 2.68 10^-10 N D. 1.07 10^-9 N

If a pilot pulls her 12.0 kg rollaboard suitcase along the ground with a force of 25. N for 10 M. The handle she pulls on makes an angle of 36.5 degrees with the horizontal. How much work does she do over the ten meter distance?

What happens to the density when water is poured into a empty glass?

A British newspaper was interested in whether groups of people who differed in social standing were treated differently when they complained to organizations about poor service they had received.

During combustion, a fuel's electromagnetic energy is converted into thermal energy.

Explain why glucose is important to a cell