Try This at Home: Seatbelt Safety
An object in motion will remain in motion unless acted upon by an outside, unbalanced force.
What You Need
- Parent or responsible adult with a driver's license
- Seat belts
What To Do
Make sure you have an adult with you to supervise this experiment.
Go for a drive in a vehicle with an adult driver. Make sure all occupants are wearing their seatbelts!
Pay attention to the road, especially when approaching stop signs or red lights.
Do you and your adult have mass? Will you obey the Law of Inertia? What are the effects of the Law of Inertia that your body will feel as the car slows down? Make a hypothesis!
Do you feel the seat belt tighten around you as the car slows down? Does it seem like your body wants to continue going forward as the car slows down?
Was your hypothesis correct? What do you think is the purpose of wearing a seat belt?
Return home safely and make sure to keep your seat belt buckled until the car is turned off.
You, your adult, and the car all have mass; therefore, you all obey the Law of Inertia. You and the adult are the objects in motion (relative to the environment). According to the Law of Inertia, you will need an outside, unbalanced force to make you stop moving. As the car slows down, you should feel the seat belt press into your stomach and chest. Your body should feel like it wants to continue moving forward. Your body wants to remain in motion but your seat belt is the outside, unbalanced force that stops you from moving. Objects with more mass require more force to overcome their inertia. A seat belt will need to exert a smaller force to slow down a child's body and a greater force to slow an adultís body. Seat belts are essential for you to be safe in the car and should be worn at all times while in a vehicle.
Mass is not the same as weight; weight depends on gravity. If you went to the moon, your mass would stay the same, but your weight would be 1/6 what it is on Earth!