Revision Flashcards
Units and Formula used to measure Energy
Joules (J)
Kilojoules (kJ)
energy transferred = force x distance
Units and Formula used to measure Speed
Metres/Seconds (m/s)
Miles per Hour (mph)
Kilometres/Hour (km/h)
speed = distance / time
Units and Formula used to measure Moment
Newton Metres (Nm)
moment = force x distance
Units and Formula used to measure Weight (a force)
Newtons (N)
weight = mass x g
Units used to measure Distance
Kilometres (km)
Metres (m)
Units used to measure Time
Hours (h)
Minutes (m)
Seconds (s)
Units used to measure Force
Newton’s (N)
Units used to measure Area
Metres square (m2)
Units used to measure Mass
Grams (g)
Kilograms (kg)
What are the three states of matter?
Give two examples of each.
Solid, Liquid and Gas
What does ‘physical change’ mean?
When a substance changes from one state to another. Eg. Water (liquid) to ice (solid)
What is the difference between a physical change and a chemical change?
In a physical change there is no chemical reaction and no new substances are made.
What does it mean to say changes of state can be reversed?
This means all the changes of state are reversible and can be undone by another process.
Eg. Ice to liquid, to reverse the process you freeze the liquid water to get ice again.
What is the process called when a substance changes straight from a solid to a gas?
Sublimation
What is the process called when a substance changes from a solid to a liquid?
Melting
What is the process called when a substance changes from a liquid to a gas?
Evaporation
What is the process called when a substance changes from a gas to a liquid?
Condensing
What is the process called when a substance changes from a liquid to a solid?
Freezing
What is the process called when a substance changes from a solid, mixes with a liquid to form a solution?
Dissolving
When a substance changes from one state of matter to another, does its mass change?
Can you give an example.
No.
Eg. Ice (20g) = Water (20g) = Water Vapour (20g)
How do the changes of state alter physical properties?
The particles in solids are packed together tightly compared to gases and liquids. This means that solids have a higher density than gases and liquids.
When you heat a substance, it changes from a solid to a liquid to a gas. The particles move further apart and the substance becomes less dense.
Ice is different though. When you hear ice, so it melts, the particles actually become closer together. So liquid water has a higher density than solid ice.
What is speed a measure of?
It is a measure of how far you travel in a set amount of time.
What are the 3 common units of measure?
Metres per second (m/s)
Miles per hour (mph or miles/h)
Kilometres per hour (km/h)
What is the formula for speed?
SIDOT
Speed is Distance over Time.
Speed = distance / time
What information do you need to know in order to work out speed?
You need to know the distance travelled and the time taken.
A hooligan sheep is skateboarding down a farmers track. The sheep takes exactly 5 seconds to ,over between two femce posts. The posts are 10 metres apart. What is the sheeps speed?
Write down what you know.
Use the formula for speed.
What do I know?
Distance = 10m Time = 5s
What is the formula for speed?
Speed = distance / time
Speed =10 / 5 = 2 m/s
What do these words mean when looking at a distance-Time graph? Slope Steeper line Flat line Downhill sections Curves Steeper curves A curve levelling off
Slope - the gradient shows that the object is moving
Steeper line - means the object is moving faster
Flat line - where the object has stopped
Downhill sections - means the object is moving back toward the starting point
Curves - means the speed is changing
Steeper curves - means the object is speeding up (accelerating)
A curve levelling off - means the object is slowing down (decelerating)
What are forces?
Forces are pushes and pulls.
Forces cannot be seen but the effects of a force can be seen.
Forces usually act in pairs.
Forces always act in a certain direction.
What are Forces measured in?
Newton’s (N)
What are forces in a diagram represented by?
Arrows
What instrument is used to measure forces?
A newton metre
Sometimes objects do not need to touch for there to be forces between them.
What are these types of forces called?
Non-Contact Forces
Fore example: gravity (an elephant will fall from the sky without touching it), magnetism (a magnet attracts a paper clip without touch it) and static electricity (the static charge o a balloon makes the hair stand up without touching it).
What are the 5 main effects of force on an objects movement?
- Speeds up or starts moving an object. Like kicking a football.
- Slows down or stops moving an object. Like air resistance will slow something down.
- Changes the direction of an object. Like hitting a ball with a bat.
- Turn an object. Like turning a spanner.
- Change the shape of an object. Like stretching and compressing, bending and twisting an object.
What is pressure?
Pressure is how much force is put on a certain area.
What is the formula for pressure?
Pressure = force/area
A given force acting over a big area means a small pressure.
A given force acting over a small area means a big pressure.
Why is someone wearing high heels more likely to sink i to snow than the same person wearing snow shoes?
Snow shoes: weight I spread over a large area so pressure is low and therefore she doesn’t sink I to the snow.
High heels: weight is concentrated over a small area so the pressure is high and she sinks into the snow.
What unit of measure does pressure used?
Newtons per metre squared
N/m2 = 1 pascal
True or false.
At sea level, the atmosphere doesn’t weigh anything.
False.
At sea level, there’s a lot of atmosphere (air) above you. The atmosphere weighs quite a bit, so it applies a high pressure.
True or false.
Atmospheric pressure decreases with height.
True.
The higher you go, the lower the pressure.
Atmospheric pressure is highest at the top of a mountain.
False.
At the top of a mountain, there’s less atmosphere above you. The atmosphere weighs less, so the pressure it applies is lower.
Atmospheric pressure is lower on mountains than at sea level.
True.
At sea level, there’s a lot of atmosphere (air) above you. The atmosphere weights quite a bit, so it applies a high pressure.
However, at the top of a mountain, there’s less atmosphere above you. The atmosphere weighs less, so the pressure applies is lower.
Atmospheric pressure stays the same wherever you are.
False.
True or false.
The pressure in liquid increases with depth?
True.
For liquids like water, the pressure increases with depth.
The pressure at the bottom of an ocean is higher than at the top.
True or false.
Water pressure causes upthrust and makes things float.
True.
If you put an object in water, it experiences pressure from all directions.
Water pressure increases with depth so the force pushing upwards at the bottom of the object is bigger than the force pushing down at the top of the object. This causes an overall upwRds force called up thrust.
A boat sinks lower i to the water until the ulthrist is equal to its weight and at this point the boat will start to float.
If the upthrust is less than the objects weight, it will sink.
