Yr 10 Physics Flashcards
What is a scalar? And examples
Speed - just a number e.g 50mph or 20m
What is a vector? Example
Number and direction e.g velocity = 50mph East
What is displacement?
Distance from start to end points
Are force, weight, acceleration, displacement ( vector or scalar ) why?
Vector, they can go in a direction e.g force pushing forwards
Are mass, speed, distance, energy vector or scalars
Scalars, they don’t have a direction e.g speed is just a number
Why is weight different to mass
Weight is mass x gravity ( 10 )
Mass = 40kg x 10 = 400N
What is the equation to work out weight from mass
Weight = Mass x Gravity
W= M x G
Give a list of forces
Push, pull, thrust, friction, upthrust, weight, air resistance, drag, water resistance, lift
what are the forces acting on a car at constant velocity ( sizes )
Air resistance, and friction pushing backwards
Thrust bigger than air resistance and friction
Normal/ contact force and weight same size
What are the forces acting on a car accelerating ( sizes )
Air resistance, and friction pushing backwards
Thrust much bigger than air resistance and friction
Normal/ contact force and weight same size
What are the forces acting on a car decelerating ( sizes )
Air resistance, and friction pushing backwards
Thrust smaller than air resistance and friction
Normal/ contact force and weight same size
What are the forces acting on a car that is stationary ( sizes )
Just normal/ contact force and weight same size
Forces on an accelerating boat
Thrust bigger, water resistance smaller
Air resistance medium but smaller than thrust
Weight and upthrust same size ( so the boat doesn’t sink or fly )
What is a resultant force
The sum effect of more than one force is called the resultant force
What is the resultant force on a box
Moving 50N left and 30N right
50 - 30 = 20N left
How do you calculate the moment
Force x distance
Force = 8 Distance = 0.2 metres Moment= 1.6
How do you calculate moments in gears
Force x gear radius
What happens if you have a smaller gear at the back
Low gear: multiplies effort, every one turn of pedals = a number of turns for wheel
What happens if you have a bigger gear at the back
High gear: less powerful
How do you find the centre of mass?
- Put a hole in one corner of the card shape and suspend from stand rod
- Use a plum line placed by the card to draw a vertical line down it
- Repeat the procedure hanging the card from different corners
Why does an object balance?
The larger the surface area of the base the more stable the shape is
It balances if the centre of mass is directly above the base
What is stability
The measure of how likely it is for an object to topple over when pushed or moved
What are the forces applied by two gears
They are equal
What is the relation between ratio of teeth, diameter and moment
They are all equal
What is the turning speed related to
Ratio of moment
Moment a: 5nm
Moment b: 2.5nm
Turning speed ratio: 5:2.5 = 2:1
Describe why an object doesn’t fall down an incline plane and then why it would
It wouldn’t because the force of gravity ( straight down ), perpendicular weight ( contact force keeping object up )and parallel weight ( weight running parallel with the slope ) are equal.
It would then fall down if the parallel weight became greater than the force of gravity, either by angle of slope or weight of object increasing
