Physics Flashcards
(22 cards)
What is a force?
A push or a pull on an object that interacts with another object.
What are the key properties of a force?
Size(Newtons) and direction.
What is the equation that links weight, mass and gravitational field strength?
w=mg
What is deformation?
Where an object changes shape. There are two types.
What is elastic deformation?
Deformation where the object returns to its original shape when the force is removed.
What is inelastic deformation?
Deformation where the object does not return to its original shape when the force is removed.
What does Hooke’s law state?
The extension of an elastic object is directly proportional to the force applied, provided that the limit of proportionality is not exceeded.
What is the formula for Hooke’s law?
F=ke
What is the area between the loading and unloading curves of the extension of an elastic object as it is stretched and unstretched?
The thermal store of the object.
What is the unit of energy?
Joules(J)
What is work done?
Work is done whenever an object moves in the direction of an applied force.
What is the formula for work done?
W=Fd
work done=force*distance
What is the formula for gravitational potential energy?
Ep = mgh
Energy=massgravitational field strengthheight
What is the formula for kinetic energy?
Ek=(1/2)m(v^2)
Energy=0.5massvelocity squared
How do you calculate transfers from kinetic energy to gravitational potential energy.
eg. A tennis ball is dropped from a height of 1.5m. If it started at rest, how fast is it moving when it hit the floor?
E before = E after
mgh1+(1/2)m(v1^2) = mgh2+(1/2)m(v2^2)
h1=1.5 h2=0 v1=0 v2=answer
(m9.81.5)+((1/2)m0)=(m9.80)+((1/2)mv2^2)
m9.81.5=(1/2)m(v2^2)
9.81.5=(v2^2)
29.81.5=v2^2
v2=5.42m/s
What is the formula for elastic potential energy?
Ee=1/2k(e^2)
What is power?
The rate at which energy is transferred.
What is the equation for power?
Power=Energy transferred/Time
P=E/t
What is the unit of power?
Watts(W)
What is efficiency?
The percentage of energy transferred into the wanted store.
What is the equation for efficiency?
Efficiency=Useful energy output/Total energy output
What are the advantages and disadvantages of using renewable energy sources as opposed to fossil fuels?
They have better environmental impacts as they don’t release CO2 into the atmosphere, and also they will never run out.
However, they are more expensive as they often involve building large structures such as wind turbines and dams, and are less reliable, for example, solar power only works when the Sun’s out.
