Topic 5 Forces Flashcards
(25 cards)
Vectors quantities
Have magnitude and direction. Eg force, velocity, displacement, acceleration and momentum
Scalar quantities
Only have magnitude and no direction. Eg speed, distance, mass, temperature and time
Contact force
Two objects have to touch for a force to act. Eg friction, air resistance, tension of ropes, normal contact force
Non-contact force
When the objects don’t need to be touching to act. Eg magnetic force, gravitational force and electrostatic force
Newton’s third law
When two objects interact the force exerted is equal and opposite on the two objects
Gravitational force
The force of attraction between masses. It makes all things fall to the ground. And gives everything weight
Mass
The amount of stuff in an object. Not a force. Measured in kilograms
Weight
The force acting on an object due to gravity. Weight is higher for objects that have higher masses. It is a force that is measured in Newton’s
The relationship of mass and weight
They are directly proportional
Free body diagrams
It describes the forces acting on an object the sizes of the arrows show the relative magnitude of the forces and the directions they are going
Resultant force
The overall force on a point or object. So the result of two forces pushing against each other
Word done to an object
When a force moves an object through a distance energy is transferred and work is done on the object
Scale drawing
They find resultant forces.
Equilibrium
When forces are balanced
Stretching, compressing and bending
When more than one force acts on an object.
Elastically deformed
When a force is applied to something and it returns to its original shape and length
Inelastically deformed
When a force is exerted on an object causing it stay in a certain position and length
What is the relationship between extension to force
They are directly proportional
What happens if you continue to extend the spring
Eventually extension will increase but force will not and it has reached maximum force
Moment
The turning effect of a force. The longer the distance from the pivot and the more energy exerted means a higher moment
Levers
Make it easier to do work. Since moment = force x distance if the moment stays the same and the distance increases the force must decrease
Gears
Gears interlock and turn in the opposite direction. Transmit the rotational effect of the force. Different sized gears change the moment so larger gear will cause a bigger moment. Larger gears will turn slower
Pressure
The force per unit area. The particles move around exert a force on the object
Pressure in liquids
Depends on depth and density. The more dense a liquid is the more particles it has so will collide and have a higher pressure. As the depth increases the number of particles above increases so the pressure increases
