P5 Homework - Retrieval Practice Flashcards
What is a contact force? Give an example.
A force that must touch to have an effect
e.g. Friction
Air resistance
What is a non-contact force? Give an example
A force that does not have to touch to have an effect
e.g. Gravity
Magnetic Force
Electrostatic Force
What is mass measured in?
Kilograms (kg)
What is weight measured in?
Newtons (N)
What is the equation for working out weight?
Weight (N) = Mass (kg) x Gravity (N/kg)
What affect do unbalanced forces have on movement?
Unbalanced forces (there is a resultant force) cause a CHANGE IN MOVEMENT e.g. speeding up or slowing down
What affect do balanced forces have on movement?
Balanced forces (NO resultant force) cause NO CHANGE IN MOVEMENT e.g. stationary or steady speed
What is acceleration measured in?
m/s2
Metres per second squared
What 2 things increase the total stopping distance?
Thinking distance (distance travelled in the time it takes to push the brake) Braking distance (distance travelled in the time it takes the vehicle to stop)
What is thinking distance?
The distance travelled in the time it takes to react and push the brake (reaction time)
What is stopping distance?
The distance travelled in the time it takes the vehicle to stop
What can affect thinking distance?
Speed
Tiredness
Drugs/Alcohol
Distractions
What can affect braking distance?
Speed
Road surface (less grip will increase braking distance)
Weather (rain/ice will reduce grip)
Condition of tyres (bald tyres will increase braking distance)
Condition of brakes
What do these parts of a DISTANCE-time graph represent?
a) A flat line
b) Straight line upwards
c) Straight line downwards
a) Flat = stopped
b) Straight line upwards = Steady speed
c) Straight line downwards = Steady speed back to start
What do these parts of a VELOCITY-time graph represent?
a) A flat line
b) Straight line upwards
c) Straight line downwards
a) Flat = Steady speed
b) Straight line upwards = Constant Acceleration
c) Straight line downwards = Constant deceleration
How can you investigate how force affects the extension of a spring (Hookes law)?
1) Use a stand and clamp to suspend a spring
2) Attach the spring
3) Add 10g mass and measure the EXTENSION (how much longer it gets)
4) Repeat with 20g, 30g, 40g, 50g
In the air track practical, how can you change the mass?
Add masses to the trolley
In the air track practical, how can you change the Force?
Add masses to the hook pulling the trolley
remember to add these to the trolley to keep the mass of the system the same
What is an air track?
How does this improve our equipment to investigate acceleration?
An air track is a track that releases a layer of air (like air hockey)
This REDUCES FRICTION
Which equation is the air track experiment designed to investigate?
Force (N) = Mass (kg) x Acceleration (m/s2)
How do you measure the extension of a spring?
Record the length of the spring before it is stretched and remove this from the final length.
This will tell you how much LONGER the spring is.
