Why might an electromagnet be used to pick up old cars in junk yards?
a. electromagnets are inexpensive and easily create revenue.
b. electromagnets are powerful and can be turned on and off easily.
c. electromagnets are easy to operate and can be run by cheap labor.
d. electromagnets are versatile and can pick up any metallic objects in the yard.

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

The heliocentric and the geocentric models of the solar system included these central principles

In the united states, tornadoes generally occur because of the freezing of ocean water underwater earthquakes meeting of cool and warm air masses shifting of warm and cool ocean currents