Forces And Spped Flashcards
Drag
A force that resists movement to slows down a moving object.
Streamlining
Where the shape of an object causes little resistance in air or in water.
Example: a cyclist sitting straight up isn’t streamlined but one who has leaned down into the bike towards the handlebars is streamlined)
Thrust
The force which makes an object move (like an engine for a plane as an example!)
Thrust is often generated by an engine, for example in a car, rocket or aeroplane.
Anomalous result
An unusual result which is hard to explain.
A measurement which is very different from other measurements taken in the same situation, so it seems unusual and hard to explain. Anomalous results are usually ignored in an investigation (ie not included when calculating a mean average) or repeated to check them.
and calculate a mean.
Control variable
The control variables are things which must be kept the same in an experiment.
Independent variable
The factor which is deliberately changed in an investigation, to find out how it affects the dependent variable.
Friction
A force which acts against the movement of an object.
Two objects rubbing together cause friction
Lubrication
Applying a slippery substance to two surfaces to reduce friction. Oil is a common lubricant which is applied to moving parts in machines, like the chain and gears on a bike.
Disipitated
When energy spreads out into the surroundings and becomes less useful.
Frictional forces
Forces which resist an object moving.
Weight
A force that acts on mass, pulling it down, due to gravity. Weight is a force and forces are measured in newtons (N).
Mass
A measure of the amount of matter an object is made out of. Mass is measured in kilograms (kg).
Matter
Any substance that has mass and takes up space by having volume. Matter can be solid, liquid or gas.
Gravitational field strength
The force that attracts one kilogram towards another massive object, like a planet. Gravitational field strength has the symbol g and it is measured in newtons per kilogram (N/kg).
Calculating weight and mass
The following equation can be used to calculate the weight of an object:
Weight = mass x gravitational field strength
Calculation motion and speed
Calculate speed using the speed equation - speed = distance divided by time.
Speed
A measure of how fast an object is moving.
Distance
Numerical description of how far apart two things are. Measured in metres.
Time
How long an event lasts, measured in seconds.
Speed equation is
Speed = distance divided by time
Distance equation
Distance = speed x time
Time equation
Time = distance divided by speed
Resultant force
The overall force acting on an object
Balanced forces
If the forces acting on the object are balanced there is no resultant force. This means the object could be travelling at a constant velocity. It could also be stationary or not moving at all.
Air resistance
A force that acts on an object which is moving through air. Air resistance acts in the opposite direction to the direction of movement, so it acts to slow down the moving object.
Normal reaction force
When an object is at rest on a surface it experiences a supportive force that acts against the weight of the object. This force acts at a right angle to the surface.
At rest
When an object is at rest it is not moving.
Weight
This is the force that acts on an object that is within a gravitational field.
Forces key points
Forces
- A force is a push or a pull that acts on an object due to the interaction with another object.
- Force is measured in newtons (N).
- Forces are divided into contact forces and non-contact forces.
Contact force
A force that act between two objects that are physically touching.
Non contact force
A force that acts between two objects that are not physically touching.
Magnitude
The size of a physical quantity.
Tension
Tension is a pulling force exerted on an object by a string, rope or rod
Friction
When two objects slide past each other they experience friction.
Friction is a force that acts between two touching surfaces and prevents or resists them moving against each other.
Upthrust
Upthrust is an upwards force that acts on an object when it is in a fluid (a liquid or gas).
Thrust
Thrust is a driving force exerted by an engine to make an object move.
Normal reaction force
When an object pushes on a surface like a table, wall or the ground, the surface pushes back on the object with a balancing force.
The normal reaction force always acts at right angles to the surface.
What was god’s promise to the Jews
That he would offer protection and land to Abraham and his descendants
