P5 Forces and Motion Flashcards
What is a contact force?
When objects physically touch for example air resistance, tension and friction.
What are non-contact forces?
When object do not physically touch. E.g. magnetic and gravitational.
What are scalars?
A quantity that only has magnitude (size).
What are vectors?
A quantity that has magnitude (size) and direction.
What is the word equation for weight?
weight (N) = mass x gravitation field strength (9.8N/kg)
What is Hooke’s Law?
Force and extension are directly proportional.
What is the word equation for force?
Force = Spring constant x extension
What is moment?
Moment is a turning force.
What is the word equation for moment?
Moment = force x distance from pivot.
What is the principal of moments?
sum of clockwise moments = sum of anticlockwise moments.
What can be used to increase moments?
Gears.
What is the equation for pressure?
Pressure = force / area
What is the other equation for pressure?
Pressure = height x density x gravitational field strength.
What is the equation for speed or velocity?
Speed/velocity = distance/displacement / time
What is the equation for acceleration?
Acceleration = change in velocity / time
How can you find displacement from a graph?
Calculate the area under the graph.
What is SUVAT?
Displacement, Initial velocity, Final velocity, Acceleration and Time.
What is Newton’s First Law?
No resultant force acts on an object, its motion will be constant.
What is Inertia?
the tendency for an object’s motion to stay constant if no force.
What is Newton’s Second Law?
Force = mass x acceleration
What is Newton’s Third Law?
For every action of force, there is an equal and opposite reaction force.
What is the equation for stopping distance?
Stopping distance = thinking distance + breaking distance
What affects thinking time?
Drugs, alcohol, tiredness and distractions.
What affects breaking distance?
Road conditions, tyre conditions, brake conditions, speed, weather conditions.
What is the equation for momentum?
Momentum = mass x velocity
What happens to momentum in a collision?
It is always conserved.
What can increase collision time?
Seat belts, air bags and crumple zones.
