P2 Sections 1-3 Flashcards
What does the gradient of a distance-time graph represent?
speed
Velocity is speed in a given …
direction
What are the units of acceleration?
m/s2
What does the gradient of velocity-time graph represent?
acceleration
How do you calculate the distance travelled from a velocity-time graph?
Calculate the area under the graph
what is the resultant force on an object if its velocity is constant
zero
What happens to the drag force as the velocity of an object increases?
It increases
what do you call the maximum speed an object can fall at?
terminal velocity
If you raise an object and increase its gravitational potential energy by 20J, the work you do on the object is …J
20 J
What is the principle of conservation of momentum?
Total momentum of a system before the collision = total momentum of a system after the collision provided that no external forces act
What are the units of momentum?
kgm/s
What is the name given to friction in a liquid or a gas?
Drag
For physics equations mass must be measure in…
kg
Name 2 car safety features that reduce impact force by increasing stopping time.
Crumple zone and airbags
A 2kg mass is accelerated by 3 m/s2 - calculate the force applied.
6N
A car is brought to rest from 20m/s in 5 seconds. What is the deceleration?
4m/s2
A skater of mass 60kg is moving at 4m/s. What is her momentum?
240 kgm/s
Calculate the velocity of a runner who completes 100m in 10 seconds.
10m/s
What is the velocity of a stationary object?
0
Friction is a force that..
opposes motion
Stopping distance =
thinking distance + braking distance
What factors affect thinking distance?
Drugs, alcohol, tiredness
What factors affect stopping distance?
Road surface, wet or icy roads, worn tyres, worn brakes
Which factor affect both thinking and stopping distance?
Speed
What is the thinking distance for a car travelling at 45m/s with a driver whose reaction time is 0.2 seconds?
9m
What is meant by regenerative braking?
A system which converts the movement energy into electricity.
If an object has no resultant force on it what happens to it’s motion?
If it is still, it will stay still. If it is moving it will continue at a steady speed in a straight line.
Newton’s 3rd law states that for every action there is ..
an equal and opposite reaction force
What is the force due to gravity called?
Weight
What are the units of weight?
Newtons
