# Newton's Second Law

## F = ma ; Force = mass * acceleration

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A Big Kick, But Big Enough?

### Can you kick a bowling ball as well as you can kick a soccer ball?

Credit: sffoghorn
Source: http://www.flickr.com/photos/sffoghorn/3307944139/sizes/o/in/photolist-63j5xD-69sjh3-6vPRgo-6LENju-7avm88-7avmgB-7avmjt-7az9L3-7az9V3-7az9Xb-7ca9kB-7gVRCx-7uBWoT-87m3J7-cdYEzd-83ZQKQ-ee9Bzp-9eZACV-dLDoyv-92MZVk-bF8ejq-cFy3HY-8AZd6o-aEi3Yd-bdTPF4-8hHYAL-8tJusS-8xC55g-8Sm4MV-bUkVjf-dh3YCP-abV8sk-a2JMMh-83WKCn-7KQe5H-7QyXFC-cdYErq-9qoPfZ-8Ztk2P-9qoPwz-bCgoyr-8NXKG2-cdGNDG-bWktGe-7UwnaG-e8oWh6-7MeLP3-8nQ3cT-az2cMU-ayYxGZ-a6pC4V/

[Figure1]

A soccer player must have an impressive kick. If he or she is doing a corner kick and wants the ball to reach the other side of the field where some teammates are waiting, he or she must put an immense amount of force into the kick.

The ball would probably soar and leave the team in a good position to score! But what if the soccer player had to kick a bowling ball in the same manner? Sure, the player might put the maximum force that he or she is capable of into the kick, but the ball would probably move only a few centimeters -- and cause a lot of pain to the player’s foot!

Newton’s second law of motion states that the acceleration of an object is directly dependent on the net force acting on it, and inversely related to its mass. The more net force that is put into an object, the more it will accelerate, but the more massive the object, the less it would likely accelerate. The equation for the second law is \begin{align*}F=ma\end{align*}.

### Creative Applications

1. It takes 270 N for a soccer player to make a decent corner kick. Assuming the soccer ball is 0.42 kg, what is its acceleration?
2. How much force would it take for the soccer player to make a 7.2 kg bowling ball move at the same acceleration as the soccer ball in the previous question?
3. A fully-loaded, parked truck has a mass of about 37 Mg (megagrams). How much force would it take to get it moving at .5 m/s2, and would a 1500-kg sports car accelerating at 11 m/s2 be able to crash into the truck and make this occur?

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