Newton's 1st Law (Inertia)
What is inertia?
The tendency of an object to resist any change in its motion.
What is the formula used to calculate Force?
F = m x a (Force = mass x acceleration).
How much force is needed to accelerate a 10 kg bowling ball at 2 m/s2.
20 N (10 x 2)
State Newton’s Third Law of Motion.
For every action force, there is an equal and opposite reaction force.
Which property of an object determines how much inertia it has: its speed, its mass, or its volume?
Its mass.
What is the unit of measurement for Force?
Newtons (N).
A soccer ball with a mass of 0.5 kg is kicked with a force of 10 N. What is its acceleration?
20 m/s2 (10 / 0.5)
When you push down on a desk with your hand, what is the reaction force?
The desk pushes up on your hand with equal force.
What state of motion will an object at rest stay in unless acted upon by an unbalanced force?
It will stay at rest.
If you apply the exact same pushing force to a full shopping cart and an empty shopping cart, which one will accelerate faster and why?
The empty cart, because it has less mass.
An engine exerts a force of 300 N on a cart, causing it to accelerate at 5 m/s2. What is the mass of the cart?
60 kg (300 / 5)
When a rocket launches, hot gas is pushed downward out of the engine thrusters. What is the equal and opposite reaction force?
The hot gas pushes the rocket upward into the air.
Why do passengers lurch forward in their seats when a bus suddenly hits the brakes?
Inertia (their bodies want to keep moving forward at the speed the bus was going).
What is the formula used to solve for acceleration when you know Force and mass?
a = f /m
A 1,200 kg car accelerates at 3 m/s2. What net force is being exerted by the engine?
3,600 N (1,200 x 3)
If a swimmer pushes backward against the water, in which direction does the water push the swimmer?
Forward.
If a hockey puck slides across a frictionless ice rink in outer space, what will happen to its speed and direction over time?
It will continue moving in a straight line at a constant speed forever.
If you double the net force applied to an object without changing its mass, what happens to its acceleration?
Its acceleration doubles.
A toy rocket weighing 2 kg accelerates upward at 15 m/s2. What total force did the thruster generate?
30 N (2 x 15)
True or False: Action and reaction forces cancel each other out to zero because they are equal and opposite. Explain why.
False, because action and reaction forces act on two different objects, not the same object.