Force Moments Work And Power Flashcards
(23 cards)
A force
Anything which cause an object to change its velocity
Velocity
Is 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 an object towards the ground
Friction
Slows down moving objects
Electric
Causes charged particles to move
Magnetic
Cause magnetic materials to move
To measure force we use
Newton spring balance
Forces always occur in pairs
For every force there’s an equal and opposite force
Friction
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
Reduces friction
Friction advantages
Helps u stop
Brakes on car
Removes rough surface (sandpaper)
Helps u walk - gives grip to stop u slipping keeps u upright
Tyres won’t spin while driving
Rub ur hands to get warm
Hitting flint and steel can make a spark to make a fire
Putting extra grips on shoes stops u slipping on ice
Friction keeps nails in wood stops them from falling out
Friction disadvantages
Braces cause blisters do to skin being rubbed
Wear down shoes
Carpet burn if u slip
Friction between air and car fuel is wasted trying to move car
Cartilage wears away at the joint = can be painful
Force
Mass x acceleration
Weight
Mass x (acceleration due to) gravity
Work
Is done when a force moves an object
Work(J)= force(N) x distance (m)
Unit of work is joules
Power
The rate something is done
Unit watt
1watt = 1j/s
Hooks law
States that the extension of an elastic body (spring) is directly proportional to the force applied to it
A straight line graph tells u that
The two things on the graph are proportional
