Some simple machines decrease mechanical advantage and are used

1.) decrease work
2.) divide distance to decrease speed
3.) multiply distance to decrease speed
4.) increase work

Point charges q1 = 51 µc and q2 = −27 µc are placed 1.0 m apart, with q2 on the right. what is the force (in n) on a third charge q3 = 19 µc placed midway between q1 and q2? (assume the positive direction is to the right. indicate the direction with the sign of your answer.)

Which scientist was the first to propose the heliocentric model of the universe? a. aristotle b. isaac newton c. galileo galilei d. nicolaus copernicus

What efficiency of a car's engine when heat input is 200,000 joules and waste heat is 150,000 joules? a. 75% b. 35% c. 25% d. 85%