What are forces?
a push or pull
What can unbalanced forces do?
Can balanced forces move objects?
What is Newton's first law of motion (state it):
Object at rest will remain at rest, moving object will remain in motion
What is another name for Newton's 1st law?
Law of inertia
What is inertia?
tendency of an object to resist change in motion
What does inertia depend on?
mass of an object
What is friction?
force of one surface against another
What does strength of friction depend on?
texture of the surfaces & how hard they are pushed together
What is Newton's 2nd law of motion?
force=mass x acceleration
What does Newtons second law mean in terms of changes in force and mass acceleration?
increase in force=increase in acceleration, increase in mass=decrease in acceleration
What is Newton's third law of motion?
every action there is an equal and opposite reaction; forces always act in pairs
What is gravity?
force of attraction between objects due to their masses
What is freefall?
only force acting on an object is gravity
What is acceleration?
the rate at which velocity changes over time
What is the acceleration due to gravity? Explain.
Every second an object is falling its velocity increases by 9.8m/s. all objects free fall accelerate at the same rate.
What is weight?
measure of the force of gravity on an object.
What is mass?
measure of the amount of matter in that object.
What is the Law of Universal Gravitation?
The force of gravity that acts between all objects in the universe, any two objects that attract each other.
What does the strength of gravitational pull depend on?
mass and distance between two objects.
How would you figure out your weight on the moon??
multiply by 1/6 of weight on earth
A change in position relative to a reference point, measured by distance and time
Frame of Reference
The point from which movement is determined
The distance traveled by moving objet per unit of time
The speed of moving objects is not always constant
Speed in a given direction
The rate of change in velocity
Term used to mean a decrease in speed:negative acceleratrion
Any push or pull
A force opposing motion
The force of attraction between all objects in the universe
An object falling under the influence of gravity: no air resistance
The effect of gravity on an object's mass
The product of the mass of an object and it's velocity
Newton's third law
Explains why forces act in pairs:for every force there is an equal and opposite reaction force
What is the speed of an object that travels 300 km in 6 hrs
What is the average speed of a train that travels 300 km in 4 hrs and another 500 km in 4 hrs?
What is the acceleration of a school bus traveling east that goes from 50 km/h to 100 km/h in 5 hrs?
Calculate the acceleration of a bicyclist traveling north that slows down from 15m/s to 5 m/s in 2 sec?
What is the Net Force?
What is the Net Force?
a force that will not cause an object to move
a force that causes an object to move
unit used to measure force
Combination of all forces acting on an object