The property of all matter, proportional to mass, that resists being accelerated by a force.
inertia
This motion term is a measure of the rate of change in an object's speed or direction of motion.
acceleration
Newton reasoned that acceleration only happens when what acts on an object?
force
It is defined as a "push" or a "pull" on an object by another object.
force
According to the first law, an object on which no force or balanced forces act will do what?
If at rest, it will remain at rest.
If in motion, it will remain in motion at a constant speed and direction.
What is the SI unit for force?
The Newton (N)
What is the SI unit for mass?
The kilogram (kg)
State Newton's 2nd law of motion in mathematical form.
F=ma
a = F/m
What is the acceleration of a 10-kg object if it acted on by a 50-N force to the right and a 30-N force to the left?
2 m/s/s to the right
A 10-kg object is accelerating while being pushed across a floor along which 30 N of kinetic friction acts on the object.
If the object's acceleration is 2 m/s/s, how much force is being applied to the object in the direction of this acceleration?
50 N
State Newton's 3rd law of motion in terms of forces.
For every action force (exerted by object A on object B), there is an equal and opposite reaction force (exerted by object B back on object A).
Describe the reaction force to the following action force:
Your weight pushes down on the chair in which you are sitting.
The chair pushes up on you with a force equal to your weight.
Describe the reaction force to the following action force:
The earth pulls down on you with a force equal to your weight (if not accelerating).
You pull up on the earth with a force equal to your weight.
A 200-kg object smashes into a 20-kg object. How do the impact forces on each of the two objects compare?
They are equal and opposite
A 200-kg object smashes into a 20-kg object. How do the impact accelerations of each of the two objects compare?
The 20-kg object experiences 10x greater acceleration than the 200-kg object (since a= F/m and they experience the same "F").
The force of gravtity exerted by the earth on objects on earth is referred to as the object's ______________.
weight
When Newton observed the effect of gravitational force on an apple falling from a tree, he extended that to include what?
He extended that (earth's gravity) to the moon and that gravity acts between all objects, even those separated by empty space.
According to Newton's law of gravity, how does the mass of the objects affect the amount of gravitational attraction between them?
An increase in the mass of either object, the greater the force of gravitational attraction between them.
According to Newton's law of gravity, how does the distance between the objects affect the amount of gravitational attraction between them?
The greater the distance between the centers of the objects, the weaker the gravitational force between them.
How did Newton describe the role of gravity in the orbits of moons and planets?
Objects in orbit are being pulled toward what they orbit by the force of gravity. They are essentially falling "around" rather that toward what they are orbitting due to having enough forward motion to follow a curved path that matches the curvature of the round body they orbit.
Is the amount of gravitational force acting on an object dependent on the object's mass?
Yes. The force of gravity on an object equals its mass x gravitational acceleration.
Does the amount of acceleration an object experiences in free-fall depend on the object's mass?
No. Acceleration equals force / mass and since F= mg the mass divides out.
mg / m = g
Here on Earth's surface, what is the value for "g" (gravitational acceleration)?
g= 9.8 m/s/s
The value for "g" on any planet or moon depends on what two factors?
The mass of the planet or moon (bigger mass = higher g) AND
The radius of the planet or moon. (bigger size = lower g)
In the presence of air resistance, what are the two main factors that affect the actual acceleration of a falling object?
speed and area of the object