3
Select the correct answer.
How does the law of conservation of energy apply to machines?
A.
Machines create energy from scratch.
B.
Machines consume energy until no energy remains.
C.
Energy transferred to a machine equals energy transferred from it.
D.
Engineers break the law of conservation of energy by using machines.

we need to know the time interval during which the force acts. impulse of force = momentum change

3. dark matter

empty space could also be a simple vacuum

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.