ATest+20C

A scissor-jack for a car uses a screw mechanism. If the jack has a mechanical advantage of 200, and your car has a weight of 2000 pounds, how hard do you have to push on the crank?

 ANSWER: MA can be calculated by output force / input force. Therefore, an input force of 10 pounds is required, assuming there is no friction, because 2000/10 = 200.