Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
26 Cards in this Set
- Front
- Back
|
1. What is ‘work done’? |
Work done is the energy transferred when aforce moves an object through a distance. |
|
|
Give the formula for work done.Say what each of the termsrepresents and what units theyshould be in. |
W = F × d.W is work done in J,F is force in Nd is distance in m. |
|
|
What is gravitational potentialenergy? |
It’s the energy that an object has because of itsvertical position in a gravitational field. |
|
|
What is the formula for workingout gravitational potential energy?What does each term represent andwhat units should they be in? |
Ep = m × g × h.Ep is gravitational potential energy in J,m is mass in kg,g is gravitational field strength in N/kgh is height in m. |
|
|
What is kinetic energy? |
It’s the energy something has because it’smoving. |
|
|
Which of these has the mostkinetic energy: a small dog walkingslowly or a large dog running fast?Explain why. |
The large dog has more kinetic energy, becausethe kinetic energy something has increases withits mass and speed. |
|
|
What is the formula forcalculating kinetic energy? Whatdoes each term represent and whatunits are they in? |
Ek = ½ × m × v2.Ek is kinetic energy in J,m is mass in kgv is speed in m/s. |
|
|
What is meant by the term‘power’? |
Power is the rate of doing work — i.e. how muchwork is done per second. |
|
|
The formula for power is: p=E/t.What does each term represent andwhat units are they measured in? |
P is power in watts,E is work done or energy transferred in joulest is time taken in seconds. |
|
|
What does the momentum ofan object depend on? |
The object’s mass and velocity. |
|
|
What is the formula forcalculating the momentum of anobject? Say what each termrepresents and what its units are. |
p = m × v.p is momentum in kg m/s,m is mass in kgv is velocity in m/s. |
|
|
What is the principle ofconservation of momentum? |
In a closed system, the total momentum beforean event is the same as after the event. |
|
|
What are regenerativebrakes? |
Regenerative brakes are brakes that extractenergy when they operate, to be stored andused later. They put the vehicle’s motor intoreverse rather than converting the kineticenergy of the vehicle into heat energy. At thesame time, the motor acts as an electricgenerator, converting kinetic energy intoelectrical energy that is stored as chemicalenergy in the vehicle’s battery. |
|
|
Name 2 different safetyfeatures found in cars and explainhow they reduce the risk of injuryfor passengers. |
Seat belts prevent you from hitting hard surfaces in the car or beingthrown out of the car. They also stretch slightly, increasing the timetaken for the wearer to stop. This reduces the forces acting in thechest. Some of the kinetic energy of the wearer is absorbed by theseat belt stretching. Air bags also slow you down more gradually and prevent you fromhitting hard surfaces inside the car. This reduces the forces acting inthe chest. Some of the kinetic energy of the wearer is absorbed bythe airbag deflating |
|
|
What is an electrical conductor?Give an example of one. |
An electrical conductor is a material in whichelectrical charge can easily move. E.g. metals. |
|
|
What causes some insulators tobecome positively charged whenthey are rubbed against anotherinsulator? |
Negatively charged electrons are rubbed off thefirst insulator and onto the other insulator,leaving the first insulator with a positive charge. |
|
|
Say whether the following objectswill attract, repel, or feel no forcewhen brought close together:Two positively charged objects. |
Repel |
|
|
Say whether the following objectswill attract, repel, or feel no forcewhen brought close together:Two Negatively charged objects. |
Repel |
|
|
Say whether the following objectswill attract, repel, or feel no forcewhen brought close together:Two Negatively charged objects. |
Attract |
|
|
What is an incompletecircuit? |
A circuit is incomplete if youcan’t follow a wire from oneend of the battery (or otherpower supply), through anycomponents to the other end ofthe cell/battery. |
|
|
What is electric current? |
A flow of electric charge. |
|
|
In what direction doescurrent flow in a circuit? |
From where there is a region of high charge (negative charge) to where there is no (zero) or low charge. |
|
|
Draw the circuit symbol for a:Lamp |
The work done (the energy transferred, measured in joules, J) per coulomb of charge that passes between two points in an electrical circuit. |
|
|
What is the formula linkingcharge, current and time? Writedown the units each quantity ismeasured in. |
I = Q ÷ t, Where: I = current in amps (A), Q = charge in coulombs (C) t = time in seconds (s). |
|
|
What is potentialdifference/voltage? |
The work done (the energy transferred,measured in joules, J) per coulomb of chargethat passes between two points in an electricalcircuit. |
|
|
What is the formula linkingpotential difference, work done andcharge? Write down the units eachquantity is measured in. |
V = W ÷ Q, where V = potential difference in volts (V), W = work done in joules (J) and Q = charge in coulombs (C).Note W (Work Done) is the same as Energy in GCSE physics. They have the same unit. So it could be V= E÷Q |
