Flashcards in 2a Deck (45)
Difference between Speed and Velocity
Speed is how fast your going with no regard for direction. Velocity however must also have the direction specified.
Distance-Time Graph equation
Speed= Distance x Time
Formula for Acceleration
Change in velocity / Time taken
Velocity-Time Graph, how to find Acceleration
Acceleration= gradient= vertical change/ horizontal change
Difference between Weight and Mass
Mass is just the amount of stuff, weight is caused by the pull of the gravitational force.
What is Mass measured in?
What is Weight measured in?
Formula relating Mass, Weight and Gravity?
Weight= mass x gravitational field strength
Define resultant force
Overall force on a point or an object
How do you work out Resultant Force?
F=ma m=mass (kg) a=acceleration in metres per second squared F=the resultant force in Newtons (N)
What is Terminal Velocity?
When falling objects first set off, the force of gravity is much more than the frictional force slowing them down, so they accelerate. As the speed increases the friction builds up. This gradually reduces the acceleration until eventually the frictional force is equal to the accelerating force and then it won't accelerate anymore. It will have reached its maximum speed or terminal velocity and will fall at a steady speed.
What two factors affect your stopping distance?
Thinking Distance and Braking Distance
What two things affect your Thinking Distance?
How fast your going, how dopey you are
What four things affect your Braking Distance?
How fast your going, how good your brakes are, how good the tyres are, how good the grip is
What is the formula for Work Done?
Work Done= Force x Distance
How do you work out somethings Gravitational Potential Energy?
= mass x g x height
(g= gravitational field strength)
How do you work out somethings Kinetic Energy?
= 1/2 x mass x speed squared
To stop a moving car, the energy is converted to...
heat energy as friction between the wheels and the brake pads, causing the temperature of the brakes to increase
Extension of an Elastic Object is Directly Proportional to Force, the equation is...
Force= k (the spring constant, N/m) x e (extension, m)
What is the limit of proportionality in springs?
The maximum force that the elastic object can take and still extend proportionally
What is the equation for Power?
Power= Work Done (or energy transferred) / Time taken
What is power measured in?
Watts or J/s
Equation for Momentum
Momentum (kgm/s) = Mass (kg) x Velocity (m/s)
Name five ways cars are designed to increase safety
Brakes, crumple zones, side impact bars, seat belts and air bags
What is the build-up of static caused by?
Explain Static Electricity
When certain insulating materials are rubbed together, negatively charged electrons will be scraped off one and dumped on the other. This will leave a positive static charge on one and a negative static charge on the other. Which way the electrons are transferred depends on the two materials involved. Electrically charged objects attract small objects placed near them.
Two things with opposite electric charges are...
Two things with the same electric charges will...
Repel each other
An example of a good conductor