june 2022 Flashcards
(15 cards)
Suggest two factors that affect the distance an electric car can travel before the battery needs to be recharged
speed
mass
streamlining of car
Explain two ways that method A is better than method B
Method A - protractor drawn on paper, laser
Method B- ray box, separate protractor
Protractor drawn on paper - you do not have to move the mirror to measure the angles/ reposition protractor
- more likely to record the correct angle of incidence/reflection
-ray in method A does not diverge
- making is easier to judge the center of the ray
Give factors that increase the braking distance of a car
Wet/ icy road conditions
poor condition of breaks
poor condition of tyres
increased mass of car
Explain why the drivers reaction time affects the thinking distance of a car
distance = speed x time
so longer reaction time = longer distance
The average speed of a car between the cameras and the average coexist of the car between the cameras are different. Why?
Velocity is a vector that includes direction and speed is a scalar
road is not straight
therefore the direction changes so the velocity changes
Why does hailstone accelerate when it falls?
There is a resultant force acting
The hailstone stops accelerating and reaches terminal velocity. Explain why
As the velocity of the hailstone increases air resistance increases
Until air resistance becomes equal to the weight of the hailstone
so the resultant force is zero
Explain the difference in the maximum kinetic energy of a hailstone with the mass of 10g and 20g
kinetic energy depends on both mass and velocity - equation
as mass increases so does
terminal velocity
kinetic energy directly proportional to mass
and kinetic energy directly proportional to v^2 so as mass doubles kinetic energy more than doubles
Centre of mass?
Point where the mass appears to be concentrated
or the point from which weight may be considered to act
Explain one property of the spring that makes it suitable for use in the balance
Deforms elasticslly
so it will return to its original length
Describe what is meant by red shift
The observed increase in wavelength of light from galaxies
As galaxies move away from us
Explain Figure 11 provides evidence for the Big Bang Theory( arrows pointing out from one point)
The furthest galaxies are moving away the fastest
At some time all galaxies started at the same point
Sometimes scientists have to change theories about the universe
There is new evidence that does not fit into the current theory
Explain why there is an alternating current in the output when the transformer is connected to a circuit
The alternating current causes a changing magnetic field around the primary coil
Creates magnetic field that changes direction in the core
this induces an alternating potential difference across the secondary coil causing an alternating current
Explain why the forces on the brick at the bottom of the pool cause the brick to be stationary
Upthrust acts upwards on the brick
Normal contact force acts upwards
Weight is equal to upthrust plus normal contact force
