P10 Flashcards
What does the greater the resultant force on an object result in?
A greater acceleration of an object
What does the greater the mass of an object result in?
A smaller acceleration for a given force
What is the equation for resultant force(F)
mass(m) X acceleration(a)
what is the intertia of an object?
Its tendency to stay at rest or in uniform motion
What is the equation for weight(W)
mass(m) X gravitational field strength(g)
What is the weight of an object?
The force acting on the object due to gravity
What does the object acting on only by gravity do?
accelerated at 10m/s2
What is the terminal velocity of an object?
The velocity it eventually reaches when it is falling
What is the resultant force of an object when moving at terminal velocity?
0
What do friction and air resistance do to the force of a vehicle?
Oppose/push against it
What does the stopping distance of a vehicle depend on?
The thinking distance and braking distance
what gives the braking force of a vehicle?
Force= mass X acceleration
What is momentum of a moving object?
Momentum of a moving object(p)= mass(m) X velocity(v)
What is the unit for momentum?
kg m/s( kilograms metres per second)
what is conservation of momentum?
Yeh total momentum before an event is the same as the total momentum after the event.
What can a closed system also be called?
Conservation of momentum
What does momentum have?
Size and direction?
What is momentum defined as?
mass X velocity
What is 2 objects total momentum if they move with different speeds and unequal masses?
0
What does the force of the impact depend on when 2 cars collide?
Mass, change of velocity and length of impact.
What happens when the impact time of a crash increases?
the impact force is reduced
Name 2 things that happen when 2 vehicles collide
The exert equal and opposite forces on eachother
their total momentum is unchanged
what is the impact force equation?
Change of momentum divided by impact time
How do cycle helmets and cushioned surfaces reduced impact forces?
by increasing impact time
How do seat belts and air bags become a safety feature?
by increasing impact time
How do side impact bars and crumple zones become a safety feature?
they give way in an impact and therefor increase the impact time
what can be used to find the speed of a car before an impact?
conservation of momentum
What is an object called if it returns to its original shape after removing the force deforming it?
Elastic
What is extension?
The difference between the length of the object and its original length
What is the extension of a spring and the force applied to it
directly proportional
What happens beyond the limit of proportionality?
the extension of a spring is no longer proportional to the applied force
What is the inertia of an object?
Its tendency to stay at rest or in uniform motion
