Newton’s first law

Newton’s 1st Law AKA the “Law of Inertia” An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

But what is inertia? Inertia – the resistance of an object to a change in its speed or direction

Skateboarding & physics Did you ever ride a skateboard? Even if you didn’t, you probably know that to start a skateboard rolling over a level surface, you need to push off with one foot against the ground. Do you know how to stop a skateboard once it starts rolling? She steps down on the back of the skateboard so it scrapes on the pavement. This creates friction which stops the skateboard.

friction Even if Laura didn’t try to stop the skateboard, it would stop sooner or later. That’s because there’s also friction  between the wheels and the pavement. Friction is a force that counters all kinds of motion. It occurs whenever two surfaces come into contact.

At rest stays at rest, motion stays in motion The first law of motion states that an object at rest will remain at rest and an object in motion will stay in motion unless it is acted on by an unbalanced force. Without an unbalanced force, a moving object will not only keep moving, but its speed and direction will also remain the same. Newton’s first law of motion is often called the law of inertia because inertia is the tendency of an object to resist a change in its motion. If an object is already at rest, inertia will keep it at rest. If an object is already in motion, inertia will keep it moving.

Skateboard: discuss How does she use Newton’s First Law to get her skateboard moving? How does Newton’s First Law of Motion help her stop her skateboard?

Quick check: in isn You don’t need to push off with a foot against the ground to start a skateboard rolling down a bank. Does this violate Newton’s first law of motion? Why or why not? Nina ran into a rough patch of pavement, but she thought she could ride right over it. Instead, the skateboard stopped suddenly and Nina ended up on the ground. Explain what happened. Now that you know about Newton’s first law of motion, how might you use it to ride a skateboard more safely?

law of inertia assistance NFL – Newton’s 1st Law - https://www.youtube.com/watch?v=08BFCZJDn9w Dr. Skateboard – Newton’s 1st Law – https://www.youtube.com/watch?v=F9COtJBBzhk

foldable What do I need in my foldable? On the outside – the name/number of law a visual representation On the inside – Definition Two examples Pneumonic/memory trick to remember this law

Newton’s 2nd law The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. F = M x A Force = Mass x Acceleration