First law
What is Newton's first law of motion about?
Inerita
What is acceleration?
Acceleration is a change in velocity
What is Newton's 3rd law of motion
For every action, there is an equal and opposite reaction.
What are Newtons?
Newtons are a unit used to measure force.
What are free-body diagrams?
Free-body diagrams are diagrams used in physics to show the forces acting upon an object
What is Newton's first law of motion?
An object at rest will stay at rest until acted upon by an unbalanced force.
An object in motion will continue in the same direction with the same speed unless acted upon by an unbalanced force.
What is Newton's second law of motion?
Force = Mass x Acceleration
What are action-reaction pairs?
Action-reaction pairs are the pair of objects which apply a force upon each other according to Newton's 3rd law of motion
What are non-contact forces? List the 3 non-contact forces.
Non-contact forces are a push or pull that act upon an object without touching.
- Gravitational force
- Electrical force
- Magnetic force
Draw a Free-body diagram:
A book at rest on a table.
Up - Normal
Down - Gravity
What does it mean if an object is at Equilibrium?
It means the forces are equal on both sides and therefore balanced.
If we were to drop a bowling ball and a feather in a room with no air, which would fall to the ground faster? Why?
Neither, they will fall at the same rate because there is no air resistance acting upon the objects.
The size and direction of the forces in action-reaction pairs are unequal and opposite
TRUE or FALSE
FALSE
The size and direction of the forces in action-reaction pairs are equal and opposite.
What are net forces? What do they cause?
Net forces means there are unbalanced forces and they cause acceleration.
Draw a Free-body diagram:
A car is driving to the right and is slowing down. Ignore air resistance.
Right - Applied (Smaller)
Left - Friction (Larger)
Down - Gravity
Up - Normal
What is the difference between a balanced and unbalanced force? (Relate this to an object's motion)
When forces are balanced, they are equal on both sides, resulting in no change in motion (velocity) for the object. Unbalanced forces are not equal on both sides, and result in a change in motion (velocity) for the object.
When does a falling object reach a constant speed?
A falling object reaches a constant speed when the air resistance acting upon the object is equal to the force of gravity acting upon the object
How does Newton's third law of motion apply to the movement of objects?
If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A.
What are contact forces? List the 6 contact forces.
Contact forces are a push or pull acting upon an object while they are touching.
- Frictional force
- Tension force
- Normal force
- Air resistance force
- Applied force
- Spring force
What is the relationship between a parachute's size and the terminal velocity of an object that is attached to the parachute. Why?
The larger the parachute the lower the terminal velocity of the object and the smaller the parachute the greater the terminal velocity of the object.
This occurs because the larger parachute will have a larger surface area, thus increasing the amount of air resistance that is acting upon the object.
Why should we wear seatbelts?
Draw a diagram and use Newton's 1st law of motion to explain your reasoning to the class.
We should wear seatbelts because if we are in a crash our body will want to continue in the same direction with the same speed forward as the car was moving before it crashed.
This means if your car is moving at 60 km/h and your car crashes and stops, you will keep moving at 60km/h!
How much acceleration does a 74kg object experience when you apply 24 Newtons to it?
0.324 m/s²
Write down 3 real -life examples of action-reaction pairs and indicate what the objects are doing (Push and pull).
- Swimming (Human pushes the water with kicks. Water pushes back against the humans legs)
- Jumping (Human pushes against the ground with feet. Ground pushes back against human's feet)
- Tennis (Racquet pushes against ball. Ball pushes against racquet)
Diagram and label all the forces present in a car driving on the road.
Forward - Applied Force
Backward - Air resistance force, Frictional force,
Down - Gravitational force
Up - Normal force
Draw a Free-body diagram:
A person sitting on a chair with wheels pushes against a wall to their right and starts moving at a constant speed. Diagram the forces acting on the person
Up - Normal
Down - Gravity
Left - Applied
Right - Friction