Which devices might use electromagnets? pick all that apply.

1. audio speakers

2. plastic combs

3. trains

4. doorbells

5. revolving chairs

6. cranes

Evolution concept map

How much force is needed to stop a 120-kg ice-hockey player if he decelerates at 20 m/s²? a. 6 N b. 240 N c. 2400 N d. 20 N

A flask containing argon gas is connected to an closed-ended mercury manometer. The closed end is under vacuum. If the mercury level in the closed arm is 230. mm above that in the arm connected to the flask, what is the argon pressure, in torr?

The frequency of a wave is 20 Hz. If the speed of the wave is 4 m/s, what is the wavelength?

Which of the following is sometimes called electrical potential? A. ohms B. amps C. voltage D. resistance

If a force of 40 newtons moves a cart a distance of 9 meters, the work done is Nm. If the same force moves the same cart three times that distance, the work done is Nm. NextReset

What is the critical angle c for total internal reflection if the material is clear acrylic, with a refractive index of 1.5?

What is happening if energy input remains constant and voltage remains the same in a circuit, but the current decreases? A. The resistance has increased. B. The volts have decreased. C. The power has increased.

The velocity - time graph of a ball of mass 25g moving on road is as given below: (a) How much force does the road exert on the ball to bring it to rest? (b) What is the direction of the force exerted by the road?

A spring required a force of 5.0 n to compress it 0.1 m. How much work is required to stretch the spring 0.4 m?