Force vs. Mass
Design and conduct experiments or simulations to demonstrate the outcome that occurs as a result of applying various amounts of force to objects that are in motion.
- Speed is a measure of how fast something moves a particular distance (for example, meters) over a given amount of time (for example, seconds).
- Therefore, speed is the rate of change of the position of an object, or how far something will move in a given period of time.
- Speed does not necessarily mean that something is moving fast.
- If an object is in motion and more force is applied to it, the object will begin moving faster.
- If two objects have the same mass and a greater force is applied to one of the objects, the object which receives the greater force will change speeds more quickly. For example if a ball is hit harder, it will speed up faster.
- If an object must be slowed down quickly, the force applied to the object must be greater than what is needed for a gradual slowing down. For example, the greater the force applied to the brakes of a bicycle, the more quickly it will slow down or stop.
- Varying the amount of force applied to a moving object can also change the direction that the object is moving more or less quickly. For example, a baseball pitched toward the batter may quickly change direction and speed if hit very hard, or may change direction and speed more slowly if hit softly as with a bunt.
- If a heavy (more massive) object is in motion, more force must be applied to get the object moving faster.
- If the same force is applied to two objects, the object with the smaller mass will change speeds more quickly. For example if a baseball and a bowling ball are thrown with the same force the baseball will speed up faster.
- In order to slow down or stop a heavier (more massive) object, the force on that object must be greater than for a less massive object. For example, if the same braking force is applied to a small car and a large truck, the car will slow down more quickly.
- It is more difficult to change the direction of a heavy moving object, than one that is lighter in mass.