P2.2 Newton's Laws Flashcards
What is a force?
A push or pull acting on an object due to an interaction with another force.
What are the two categories that all forces can be split into?
- Contact
- Non-contact
Give three examples of contact forces.
- Friction
- Air resistance
- Tension
Give three examples of non-contact forces.
- Gravitational forces
- Electrostatic forces
- Magnetic Forces
What is the name given to the single force that is equivalent to all other forces acting on an given object?
The resultant force
State Newton’s first law for a stationary object.
If the resultant force on a stationary object is zero, the object will remain at rest.
State Newton’s first law for a moving object.
If the resultant force on a moving object is zero, the object will remain at a constant velocity.
If an object changes direction but remains at a constant speed, is there a resultant force?
Since there is a changr in direction, there is a change in velocity and so there must be a resultant force.
When does an object fall with terminal speed?
- When the upwards forces and the downward forces are equal
- No resultant force, so there is a constant speed
What happens to the magnitude of air resistance on a falling object when the velocity increases?
As velocity increases, the force of air resistance on the object will also increase.
State the defining equation for Newton’s Second Law.
Resultant force = Mass x Acceleration
State Newton’s Second Law in words.
An object’s acceleration is directly proportional to the resultant force acting on it and inversely proportional to its mass.
What is inertia?
The tendency of an object to continue in its state of rest or uniform motion.
What is inertial mass?
- A measure of how difficult it is to change a given object’s velocity
- The ratio of force over acceleration
State Newton’s Third Law.
Whenever two object;s interact, the forces that they exert on each other are always equal and opposite.
