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.

explain a method applied to test a diesel engine at constant speed at list the method used to measure the friction power

What instrument uses a magnetic field to magnify imags up to 100000000?

What type of ions are electrons colliding with to cause resistance in a circuit? A. Metalloids B. Metallic C. Gases D. Non-metallic

Compared with the peak wavelength given off by the sun, what is the peak wavelength given off by a hotter star? A.) shorter in wavelength and higher in energy B.) shorter in wavelength and lower in energy C.

According to a simplified model of a mammalian heart, at each pulse approximately 20 g of blood is accelerated from 0.25 m/s to 0.35 m/s during a period of 0.10 s. What is the magnitude of the force exerted by the heat muscle?

An object with a mass of 10.9 kg experiences a force of 18.53 N. What is the acceleration of the object? A. 2.2 m/s2 B. 1.7 m/s2 C. 16.83 m/s2 D. 1.3 m/s2

A proton, starting from rest, accelerates through a potential difference of 1.0 kV and then moves into a magnetic field of 0.040 T at a right angle to the field. What is the radius of the proton's resulting orbit

Which of the following terms are needed to completely describe speed? Check all that apply. A. Units B. Direction C. Number D. Mass

Drivers are able to see objects ahead of them because light travels through windshields.

How are trade winds affected by the coriolis effect