   
Seibun Mind-Development® Activities
Hovercraft LAB 2 – Newton’s Second Law of Motion
Unbalanced Forces
Information
Sir Isaac Newton developed three laws of motion. The Newton’s Second Law of Motion states an object will change its state of motion when acted on by an unbalanced, outside force.
Changing motion is also called acceleration. The motion of an object can be changed in one of two ways. The object can change speed by moving faster or by slowing. An example of this type of acceleration
is seen as a car moves faster when the gas pedal is pushed. It is also seen when a car slows as the brake pedal is used. Both using a gas or brake pedal causes a force. An unbalance or unopposed force on an object causes an acceleration.
The change in motion or acceleration is related to the force and the size of the object. The force is the push or pull on the object. The size is how much of the object is being pushed or pulled.
This law is could be understood you imagine a group of kids playing with a wagon. There is an unwritten understanding in the group of kids. The rule is the big kid never gets to ride. The big kid can apply the biggest force to pull or
push the other kids. It is harder to push or pull the big kid. So the big kid always seems to push or pull but never get a ride. If the big kid does get a ride, it is never as fun or fast as it is for the smaller kids.
Equipment – Seibun Hovercraft, smooth surface (rectangular cookie sheet and water works well), tape, pennies or other coins.
Procedure
1. Find a smooth and level surface. Filling a large, rectangular cookie pan with water works well for a very level
and smooth surface. 2. Turn on the Hovercraft then place it on the smooth surface.
3. Notice the Hovercraft floats above the surface. 4.
Try the Hovercraft out and observe the direction the Hovercraft moves. 5. Adjust the fan so the Hovercraft
moves forward in a straight line. 6. Notice how fast the Hovercraft can move across the surface.
7. Tape a coin on each side of the Hovercraft. Be sure to put the same type of coin on each side of the Hovercraft to keep it balanced and floating evenly above the surface.
8. Release the Hovercraft and notice how fast it moves across the surface. 9.
Keep adding coins (be sure to keep the same number on each side of the Hovercraft) and observing how the Hovercraft moves across the surface. 10.
Notice how far off the surface the Hovercraft floats. This is the same idea as moving the Hovercraft forward. The force downward by the fan must balance out the weight of the Hovercraft and all the coins.
11. If the fan were to turn faster and no coins added to the Hovercraft, then how might the motion be changed? See if you can develop a way to make the fan turn faster WITHOUT adding more
batteries (more mass) to the Hovercraft. Conclusion
1. Explain to tell when a force acts on an object.
2. Explain to recognize an unbalanced force. 3. Draw
a picture of the Hovercraft as it sits on a surface without the fans on. Show and label all the balanced forces acting on the Hovercraft. 4.
Draw a picture of the Hovercraft as it moves forward with an acceleration. Show and label all four forces acting on the Hovercraft. Put a circle around the BALANCED FORCES. |
