This applet is an example of Newton’s First Law in action.
To try this
simulation:
Click on the "Launch" to knock the bottom puck to the side.
Click on the reset button to re-stack the pucks.
What's Going On?
Newton’s First Law states that:
Every object continues in its state of rest or motion in a straight line at a constant speed, unless it is compelled to change that state by forces exerted upon it.
In other words, anything with mass tends to stay in whatever position it is in. If it is moving, it stays moving. If it is still, it remains still. When you click on the launcher button, the energy from the launcher arm is transferred to the bottom puck and it shoots off to the side. The rest of the pucks do not receive that energy because they are not directly connected (glued or fastened) to the bottom puck. Their tendency (inertia) to remain at rest keeps them in place. Left without the support of the bottom puck, they simply fall to the surface in the same position that was previously occupied by the bottom puck.
There's More!
Space travel depends on Newton’s First Law. When you drive a car here on Earth, the engine has to keep running (by burning fuel) in order to keep the car moving. Otherwise friction will first slow and then stop the car.
In space there is no friction since the spacecraft is not in contact with anything (including air). Once the spacecraft is moving in a particular direction, it will keep moving until a force acts on it to speed it up, slow it down, or change its direction.
The spacecraft’s continuing movement must be accounted for when astronauts conduct experiments in space. Suppose the experiment involves growing large crystals in a zero gravity environment. If the spacecraft suddenly moves, the sudden motion (according to the First Law) will cause the crystal to move, possibly snapping the crystal from its base.
