Mechanics Flashcards
Impulse
The product of force and time, or change in momentum
2 ways to reduce injury in a car crash
Crumple zones
Seat belts
Reduce maximum force by distributing momentum over a longer period of time
Total sum of momentum after a collision or explosion
0Nm
Elastic collisions
Kinetic energy is conserved
Inelastic collisions
Kinetic energy is not conserved and transferred to other types of energy
What happens when 2 particles collide head on when one of them is stationary?
All momentum is transferred to the stationary particle
What happens when 2 particles of the same mass collide not head on?
They move at right angles to each other
What is a scalar quantity?
Only has magnitude
What is a vector quantity?
Has magnitude and direction
What is the resultant force of a system in equilibrium?
0Nm
What is a moment?
The force about a turning point
Where is the centre of mass?
The point around which the resultant torque due to gravity is 0
What is energy?
The ability to do work
What is power?
How quickly something transfers energy
What is efficiency?
A measure of how much energy is wasted
What is kinetic energy?
Energy a moving object has
What is gravitational potential energy?
He energy due to the position of an object
What is a couple?
A pair of parallel forces in opposite directions that cause a turning motion
What is torque?
The moment of a couple
How can you increase the stability of an object?
Widen the base or lower the centre of mass
What is Newton’s 1st law?
An object will remain stationary or at a constant velocity unless acted on by an external resultant force
What is Newton’s 2nd law?
Acceleration is directly proportional to external resultant force
What is Newton’s 3rd law?
Each force exerts an equal and opposite force of the same type
What is terminal speed?
The speed reached when the weight of an object in free fall equals the forces of drag
What is elastic potential energy?
Energy stored in a stretched or compressed object
