Newton's second laws
F = ?
F = m x a
a push or pull that one body exerts on another
force
In Newton's 2nd law, Force is _________ proportional to acceleration
directly
what force causes an object to try and not change
Inertia
what force opposes the motion of objects
friction
What is the force called that attracts any two objects
Gravity
forces that are not equal
net force
In Newton's 2nd law, mass is __________ proportional to acceleration
inversely
when the size of an object increase what also increases with it
The object's Inertia
Every action has an _______ and _______ reaction.
equal and opposite
a = 50 m/s2 , m = 4kg F = ?
200 N
What happens if the net force acting on an object is zero
The object will not change
Tony the dog has a mass of 30kg on Earth. What is his mass on the moon?
30kg
Mass is the same, weight is different
An object that is still will only change if acted upon by what
net force
Give an example of the third law
rocket, sitting in a chair, hitting something etc
A 7 kg shopping cart comes to a stop in 2 seconds after initially traveling at 3.5 m/s. a. What is the acceleration of the cart? b.How much net force was applied to stop the cart?
a: -1.75 m/s2
b: 12.25 N
What happens if the net force is any nonzero number
The object will accelerate negatively or positively
Tony the dog weighs 70 pounds on earth. Will he weigh more, less, or the same on the moon?
less- gravity is less
An object with a lot of inertia is likely to do what
Resist change
What is the equal and opposite force that opposes gravity called?
normal force
A net force of 345 N accelerates a boy on a sled at 3.2 m/s2. What is the combined mass of the sled and boy?
107.8 kg
A box is experiencing a force of 50N to the left and a force of 70N to the right. What is net force?
20 N right
A car starts from rest and 5 seconds later it is going 50 m/s. What is the acceleration of the car?
10 m/s2
A car rolling down a hill will keep rolling unless acted upon by a net force what is this an example of
Inertia
Explain standing on a skateboard and pushing against a wall is a good example of Newton's 3rd Law
Applying a force on the wall applies an equal but opposite force on you. Since the wall is more massive, and you have less friction, you move away from the wall.