Which best compares a brush and a commutator in an electric motor?

Some fuels are classified as nonrenewable because they -

Are remains less likely to become fossils if they are covered quickly by sediment

A karate expert breaks a stack of bricks with his bare hand. If the force applied is 520 newtons and the impact time is 5.0 * 10-4 seconds, what is the value of impulse?

Group polarization is most likely to occur in a group in which

A 5.6 V battery is connected in series with a 41 mH inductor, a 100 Ω resistor, and an open switch. At what time after the switch is closed (t=0) will the current in the circuit be equal to 12 mA?

A squirrel sitting on the ground starts to run with an acceleration of 5.1 m/s 2. How fast is the squirrel going after 0.25 seconds? A. 20.4 m/s B. 1.28 m/s C. 0.49 m/s D. 3.1 m/s

Describe how the competition between invasive and native species might affect a food web

Which vector should be negative? any vector whose magnitude is less than 1 a displacement in the direction North any vector whose magnitude is greater than 1 the velocity of a falling object

Acceleration is a scalar quantity true or false

Find a numerical value for rhoearth, the average density of the earth in kilograms per cubic meter. Use 6378km for the radius of the earth, G=6.67*10-11m3 / (kg⋅s2), and a value of g at the surface of 9.80m/s2.