Topic 5- Forces

Created by

Khloe

Cards (46)

What do vectors have?
Magnitude and direction.
Give examples of vector quantities:
force, velocity, acceleration, displacement
What do scalar quantities have?
Magnitude only and no direction.
Give examples of scalar quantities:
speed, distance, mass, temperature, time
What is magnitude?
Magnitude refers to the size or extent of something.
What 2 things can forces be?
Contact and non-contact.
Name some contact forces:
friction, air resistance, tension in ropes
Name some non-contact forces:
magnetic forces, gravitational forces, electrostatic forces
What is a gravitational force?
The force of attraction between objects with mass.
What is mass?
A measure of the amount of matter in an object.
What is weight?And what units are used?
The force exerted on an object due to gravity.
Newtons
What does weight depend on?
Gravitational force.
What is a resultant force?
The overall force acting on an object.
What happens when a resultant force moves an object?
Work is done and energy is transferred
What does an equilibrium mean in forces?
When the forces on it are balanced.
What is elastic deformation?
Temporary change in the shape of a material under a force, which is reversible when the force is removed.
What is inelastic deformation?
Permanent deformation of a material even when force is removed.
What is the required practical for elasticity?
Stretching a spring using weights and measuring the extension.
What is speed?
The rate at which an object moves.
What is velocity?
The rate at which an object moves in a specific direction.
What is acceleration?
The measurement of how quickly you are speeding up.
What does uniform acceleration mean?
Constant acceleration.
What is drag?
Resistance force acting on an object moving through a fluid.
What does terminal velocity depend on?
Shape and area.
What is terminal velocity?
The maximum velocity an object can reach while falling through a fluid.
What is Newton's first law?
Inertia- a force is needed to change motion.
What is acceleration proportional to?
The resultant force.
What is Newton's third law?
For every force, there is an equal and opposite reaction.
What is the stopping distance?
Thinking distance + braking distance.
What force does braking rely on?
Friction
What is the equation for momentum?
momentum= mass times velocity
How can you find resultants forces?
Use scale drawings- draw a straight line from starting force to end force and measure the line to find resultant force
When is an object in equilibrium?
When forces on it are balanced
What is a moment?
The turning effect of a force
How do you increase the moment?
Increase distance from pivot at which the force is applied
What do levers do?
Make it easier to do work as it increases the distance from the pivot (less force is needed to get the same moment)
What is pressure? 
The force per unit of area
What does pressure in a liquid depend on?
Depth and density
What do objects in fluids experience?
Upthrust force (resultant force)- is equal to the weight of the fluid that has been displaces by the object
When do objects float?
If its weight is equal to upthrust (forces are balanced)- an object that is denser than the fluid is unable to displace enough fluid to equal its weight, so it doesn't float