P1 - Force, energy, momentum Flashcards
What is a scaler?
wheat is a vector?
examples?
A scalar quantity has no direction just magnitude - distance, speed, time, energy
A vector has direction and magnitude - displacement, velocity, acceleration, momentum
How do you find the resultant force of a vector when using a right angle triangle?
Pythagoras
What is a vector triangle? what does it mean?
When there are 3 forces, you can join them together into a triangle, if all the lines are closed than the triangle is in equilibrium.
What is the definition of a moment?
What affects the size of the moment?
A moment is the turning effect of a force around a point. The moment of a force depends on the size of the force and how far away the force is applied from the turning point
what is the principle of moments?
For a body to be in equilibrium, the sum of the anticlockwise moments about any point must be equal to the sum of the clockwise moments about the same points
what is a couple?
A couple is a pair of forces of equal size which act parallel to each other but in opposite directions. Produces a turning effect
What’s the definition of the centre of mass?
Is the single point that you can consider the whole weight of the object acts through
What is newtons 1st law of motion?
2nd?
3rd?
Newtons 1st law states, An object will continue to move at constant velocity to be at rest unless upon by an external force.
Newtons 2nd law states, An objects rate of change of momentum is proportional to the resultant force acting upon it
Newtons 3rd law states that, when an object rests on a table, the object exerts a downward force, The table exerts a reaction force equal in magnitude and opposite in direction back onto the object
What is the impulse? where is it on a force time graph?
Impulse is defined as the product of the force and time. A it is the change of momentum.
Its the area under a force time graph
What is work?
any situation where energy is being transferred
What is efficiency equation?
useful output energy/ input energy
what is k and L in the spring equation?
k is spring constant
L is extension
What’s an elastic collision?
An elastic collision is where both momentum and kinetic energy is conserved
what’s an inelastic collision? what happens to linear momentum?
an inelastic collision is where some of the kinetic energy is converted to other forms.
linear momentum is always conserved still tho.
what is the principle of linear momentum?
Assuming no external forces act linear momentum is always conserved , so momentum before = momentum after the collision.
