physics p2 cram Flashcards
Examples of scalar quantities
Scalars : speed, distance
Examples of vector quantities
Vectors: force, acceleration
Examples of contact forces
Contact forces: friction, tension, air resistance, normal contact force
Examples of non-contact forces
Non-contact forces: gravitational, magnetic, electrostatic
What is a newton metre?
A newton meter measures weight with spring-balance
What does an object’s weight depend on?
An object’s weight depends on the gravitational field strength
What does elastic mean?
Elastic means the object returns to its original shape after all forces have been removed
What does inelastic mean?
Inelastic means the object does not return to its original shape after all forces have been removed
What happens in inelastic deformation?
In inelastic deformation, all energy is transferred to object’s elastic potential energy store
What is upthrust equal to?
Upthrust is equal to weight of liquid that has been displaced by object
What happens when an object is less dense than the liquid it is in?
When an object is less dense than the fluid, there is more upthrust and so the object will float
What happens when an object is more dense than the liquid it is in?
When an object is more dense than the fluid, there is less upthrust and so the object will sink
What is atmospheric pressure caused by?
Atmospheric pressure is created on a surface by air molecules colliding with the surface
What happens to atmospheric pressure when the height above earth increases?
Atmospheric pressure decreases when the height above earth increases because the number of air molecules increases so weight of air above surface decreases
What is displacement? (physics terms)
Displacement is a vector quantity, which is the distance of direction in a straight line from an object’s starting point to it’s finishing point
What does it mean about velocity when an object is in circular motion?
An object is in circular motion means the direction is always changing so the velocity is always changing
How do you find acceleration on a velocity-time graph?
Acceleration can be found by drawing a tangent on the curved part of a velocity-time graph
How do you find the distance travelled in a certain amount of time on a velocity-time graph?
Distance travelled in a certain time is the area under a section of the velocity-time graph
What is drag?
Drag is the frictional force caused by any fluid on a moving object
What happens to an object when the force of gravity is greater than the frictional force?
When the force of gravity is greater than the frictional force, the object accelerates and speed increases, so friction increases
What is the role of parachutes?
Parachutes increase air resistance to lower the terminal velocty
How do you calculate stopping distance?
Stopping distance = thinking distance + braking distance
What factors increase thinking distance?
Increasing distance is increased by: faster vehicle speed, slow driver reaction times
What factors increase braking distance to stop whilst brakes are applied?
Braking distance increased by: faster vehicle speed, poor road surface, wet or icy weather
What is the work done when stopping a vehicle?
Driver brakes, causing brake pads to be pressed onto wheels > friction between them causes work to be done > energy transferred from kinetic energy stores of wheels to thermal energy stores of brakes > brakes heat up
What can large deceleration cause?
Large deceleration can cause brakes to overheat and vehicle to skid
What does the conservation of momentum state?
Conservation of momentum states that in a closed system, total momentum before an event equals the total momentum after an event