P10 FORCE AND MOTION Flashcards
What is Newtons second law?
F=ma
The idea that the acceleration is proportional to the resultant force on the object.
And is inversely proportional to the mass of the object.
What is Inertia?
The tendency for the motion if an object to remain unchanged unless a resultant force is acted upon it
It can also be defined as Force/Acceleration
What is acceleration?
When the resultant force of an object is the same direction as the velocity.
What is deceleration?
When the velocity of an object decreases (if the resultant force is in the opposite direction to its velocity)
What is terminal velocity?
when an objects resultant force is zero so it acceleration is also zero
How do you work out stopping distance?
stopping distance = thinking distance + braking distance
What does the braking force depend on?
The speed of the vehicle when the brakes are first applied
The mass of the vehicle
What is thinking distance? (include the equation)
the distance travelled by the vehicle in the time it takes for the driver to react (thinking distance = speed x reaction time)
What is braking distance?
the distance travelled by the vehicle during the time the braking force acts
Name three factors that affect stopping distances?
-Tiredness, alcohol/drug consumption
-The velocity at which the vehicle is travelling
-The road condition (eg if its icy the friction is less therefore it will take longer)
-The condition of the vehicle
What is the equation for momentum?
p=m x v
momentum = mass x velocity
What is the conservation of momentum?
The idea that (in a closed system) that the total momentum at the start of the event is equal to the total momentum at the end
Finish the statement:
The longer the impact time..
the more the impact force is reduced
What is the equation for impact force?
Force = (mass x change in velocity) / time taken
What are the purposes of a bike helmet?
To increase the impact time then, subsequently decreasing the overall impact force
