Magnetism Flashcards
What do like and unlike poles do?
Like poles repel, unlike poles attract.
What is a compass?
A magnet that is free to rotate.
What is a magnetic field?
The space around a magnet where a magnetic force can be seen.
Ways to show magnetic fields?
Using iron fillings or plotting compasses.
Where do magnetic field lines go?
From the North Pole to the South Pole of the magnet.
Materials magnets can be made of?
Iron, steel, cobalt and nickel
These materials = attracted by magnets.
Uses of magnets?
Compasses
Scrap yards
Fridge doors
How would you plot the magnetic field around a bar magnet using plotting compasses?
Compasses placed around a bar magnet
Pointers point
What is magnetism?
The force of attraction
Why does a compass always turn North?
Its North Pole is attracted to the earths geographical South Pole
Define a force
Something that causes an object to change speed or direction
What are forces measured in?
Newtons (N)
Name some examples of force
Push, pull, friction, magnetic, Gravity, weight.
Name an instrument used to measure a force
Spring balance
Define weight
The weight of an object on the earth is the force of attraction between the earth and the object
What is weight measured in?
Newtons
What is the force formula to find something’s weight?
Weight= mass (in kg) x acceleration due to gravity (10)
Acceleration an object gets from the earth?
Is the same for all objects (10m/s²)
Distinguish between mass and weight
Mass
- Measured in kg - Fixed (never changes) - Fixed feature of all things
Weight
- newtons - varies and depends on where you are - is a force or pull on something
State Hooke’s Law
The extension of a spring depends on the size of the weight attached to it
What is a moment??
How much force can turn on a object
Moment formula
Force x distance from the fulcrum
Explain what a lever and fulcrum are.
A lever is a rigid body which is free to rotate about a fixed point called a fulcrum.
What is an example of a fulcrum?
The middle of a seesaw
What is an example of levers?
Door, door handle, scissors
State the law of the lever
When a lever is balanced the sum of clockwise movements = the sum of anti clockwise movements
What is the centre of gravity on an object
Centre where All the weight of the object appears to act.
i.e centre of weight
e.g you can balance a Pen on a finger if the finger is a the pen’s centre of gravity (if not the one will fall)
What needs to happen for an object to be stable under gravity
Centre of gravity should be low as possible
Area of base should be large as possible
What is equilibrium?
When an object is balanced it needs to
- not topple easily when a small force is applied
- it is unstable equilibrium if it will topple easily when small force is applied
