Force, Moments, Work And Power Flashcards
(23 cards)
Force
Anything which causes an object to change its velocity
Velocity
The speed in a given direction
Forces are measured in
Newtons
Push
Changes the velocity of an object
Pull
Changes the velocity of an object
Weight
Moves objects towards the ground
Friction
Slows down moving objects
Electric
Causes charged particles to move
Magnetic
Causes magnetic materials to move
To measure force we use a
Newton spring balance
Forces always occur in pairs
For every force there is an equal and opposite force
Friction
The force that prevents easy movement between two objects in contact
High friction
Sand paper, car tyres and rough soled shoes
Low friction
Wet soap, ice and glass
Lubricant
Anything that reduces friction
Friction advantages
Helps you stop, brakes on your car, removes rough surfaces (sandpaper), helps you walk, gives you grip to stop slipping, tyres wont spin while driving, keep you upright when walking, tyres don’t skid when driving (around corners), when cold you can rub your hands to get warm, hitting flint and steel you can make a spark to make a fire, putting extra grips onto shoes stops slipping you on ice, friction keeps nails in wood, and stops them falling out
Disadvantages of friction
New shoes, braces cause blisters due to skin being rubbed, wear down new shoes, can get carpet burns if you slip, when driving, there is friction between the air and the car, so fuel is wasted trying to move the car, cartilage wears away at the joint and can be painful
Force
Mass x acceleration
Weight
Mass x (acceleration due to) gravity
Work
Is done when a force moves an object. Work = Force x distance
Work and energy are measured in joules
Power
The rate at which work is done. Power is measured in watts, where 1 watt = 1j/s
Hooke’s Law
States that the extension of an elastic body (a spring) is directly proportional to the force applied to it
A straight line graph
Tells you that two things on the graphs are proportional
