core questions Flashcards
What is a force
A push , pull, twist or turn
What is the unit of force
Newtons (N)
What do we call forces that require touch to be felt
Contact forces
What do we call forces that act at a distance
Non-Contact forces
What is the sum of all the forces acting on an object called
Resultant force
What do we say if the forces on an object are balanced
The resultant force is zero
What do we call the force that moves an object
Thrust
What force acts in the opposite direction to the force applied
Reaction force
What force acts in a stretched cable/rope
Tension
What is the attractive force that acts between matter called?
Gravity
What force acts towards the ground?
Weight
What force acts lifting an object upwards in a fluid
Upthrust
What force acts in the opposite direction to motion
Friction/Air Resistance/Water Resistance/Drag
What is friction
A force that acts between surfaces in the opposite direction to motion
What can friction do to an object
Slow an object down
What is friction in a fluid
Drag/Air Resistance/Water Resistance
Where is friction useful
Grip between two surfaces/brakes
Where is friction not useful
Between moving parts in machines/slowing down objects moving in a fluid
What is used to reduce friction
Lubricants(e.g. oil, graphite)
What happens when friction occurs between moving parts?
Kinetic energy is transferred to heat and sound energy
What is a stationary object
An object that is not moving
What is speed
The distance travelled in a quantity of time
What is the equation for calculating speed?
speed=distance/time
What are the units of speed
m/s
What is a change of speed
Acceleration
What happens when there is a resultant force on an object?
It will accelerate (speed up or slow down)
What happens when there no resultant force on an object?
It will remain stationary or remain at a constant speed/velocity
How can we represent a journey?
On a distance-time graph
