Newton's Laws
What is Newton's first law?
An object at rest will remain at rest and an object in motion will continue moving at a constant velocity unless acted upon by a net force
A push or pull that one thing exerts on another
Force
Newton's first law is also called the law of _________
Inertia
A tennis ball and a bowling ball are pushed with the same amount of force.
Which will accelerate faster?
The tennis ball
True or False:
Action and reaction forces are not equal
False
What is the formula for Newton's second law?
F = m a
True or false:
A net force of zero leads to constant acceleration.
False
If no unbalanced forces act on a moving object, what will happen?
It will continue to move
As force increases, acceleration _________
Decreases
The action force of a rower is to push water with their paddle. What is the reaction force?
The water pushes the paddle (which also pushes the boat!)
What is Newton's third law of motion?
For every action there is an equal and opposite reaction force
When an unbalanced force acts on an object; the object _____________
accelerates
A stationary (not moving) object will only start moving if ___________________________
It is affected by an unbalanced force.
A bicycle and a truck both accelerate at the same rate. Which is being pushed by the stronger force, and why?
The truck: An object with more mass requires greater force to achieve the same acceleration
Why does it hurt to do a belly flop into a pool of water?
Because the water hits you with the same amount of force you hit the water (reaction force).
Which of the 3 laws apply when shooting a basketball?
All 3 Laws
The sum of all forces acting on an object is called the _________
net force
Name 2 reasons why inertia is more obvious in space than it is on Earth.
1) No gravity
2) No friction/air resistance
If the mass increases, the acceleration _________
decreases
True or False:
One object experiences both the action and reaction force for one collision
False - Two objects, one experiences the action force, the other experiences the reaction force
What is the wording of Newton's 2 law? (Close enough is good enough)
The acceleration of an object is directly proportional to the net force acting on it.
A combination of forces that result in no acceleration must be _________
Balanced OR Equal and opposite
I start pushing forwards on a shopping trolley, but it does not move. What must be happening?
There must be an equal force pushing against the trolley in the opposite direction, so the total forces are still balanced.
(I was pushing it against a wall)
If an object has a mass of 5kg and is being thrown with 10N of force, how fast is its acceleration?
2 m/s/s
When a golf club hits a golf ball, why doesn't the reaction force send the golf club flying backwards?
Although the golf club does feel a reaction force, the force is only large enough to decelerate the club, not to send it in the other direction.