Impulse Can Change Momentum a Lot by Making an Object Go Really Fast
Impulse is equal to force multiplied by time. In other words, if you want to change an object's momentum (or velocity) a lot, apply a LARGE force over a LONG period of time.
For instance, if you want to change the velocity of a baseball a lot, hit the baseball hard, and follow through with the hit. Following through increases the time over which the force acts on the baseball. When you try to hit a home run in baseball, you are really trying to change its velocity a lot. Think about it: the baseball is originally traveling toward you (probably really fast), and when you hit it, you not only want to make the ball go really fast, but you also want to change the direction the ball is traveling. Let's say that the baseball is initially traveling towards you at a velocity of -75 miles per hour, and when you hit it, it travels away from you at +100 miles per hour (velocity is now positive because the ball changed directions). The ball's change is velocity is its final velocity - its initial velocity, or 100 miles per hour - (-75 miles per hour) = 175 miles per hour. When you hit the baseball, you changed its velocity by 175 miles per hour! That's huge. In order to make such a large change in the ball's velocity, you must exert a huge force on the baseball over a long time. In other words, you must hit the ball hard and follow through when you swing the bat. |
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If you want to change the velocity of a golf ball a lot, you need to exert a large force on the golf ball over a long period of time. In other words, you should hit the ball hard, and you should follow through with the swing. |
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Impulse Muzzle Velocity Self-Quiz
Scroll to the top of the page and read the material BEFORE you attempt the quiz. Then, try to answer the question in the quiz.
- If you want to design a cannon with a large muzzle velocity, you make the barrel really long. Why?
- The longer barrel increases the force acting on the cannon ball.
- The longer barrel increases the time over which the force acts on the cannon ball.
- The longer barrel increases the acceleration of the cannon ball.
- The longer barrel helps the cannon ball overcome its own inertia.
- The longer barrel looks cool.