Units and formulas Flashcards
What is the unit for charge and what is its letter
Coulombs (Q in formula, C when written)
Coulombs = time x amps
What is the unit for currant and what is its letter
Amps (I in formula A when written)
Amps = coulombs / time
What is t
Time (seconds)
What is The unit for the difference in energy across a component in a circuit
Potential difference / volts (V in formula and written)
What is the unit for energy
Joules and written as (J)
Joules = currant (amps) X potential difference (volts) X time (seconds)
What is unit for resistance in a circuit
Ohms
What is the formula of potential difference
V = I x R
Potential difference = currant (amps) X resistance (ohms)
What is unit and formula of power
Power = watts Watts = joules per second e.g 1 joule per second = 1 watt Watts = currant (Amps A) x (potential differenceV) P = I x V
Formula for speed
Speed(m/s) = distance(m) / time taken (s)
What is sign and formula of acceleration
Aceleration = a
Acceleration(m/s^2) = change in velocity(m/s) / Time(seconds)
a = (velocity 2 - velocity 1)/t
Velocity 2 is the velocity the object now has
Velocity 1 is the velocity the object had
t is the time taken for change in velocity
What is force measured in
Newtons (N)
Formula of resultant force
Larger force - smaller force
What happens if the resultant force is 0 and what happens if the resultant force is greater than 0
If it is 0, the velocity will stay constant, if it is greater than 0, it will accelerate in the direction of the force.
What does acceleration depend on
The size on the resultant force and the mass of the object.
What s the formula for force needed to accelerate an object
Force(N) = mass(Kg) x acceleration(m/s squared)
F = m x a
1 newton will accelerate a 1 Kg object by 1m/s squared
Unit for gravitational field strength
N/Kg
What is the formula for weight
Weight(N) = mass(Kg) X gravitational field strength (N/Kg) W = m x g
What is the weight of a 300Kg landing craft on earth
W = m x g W = 300Kg x 10N/Kg W = 3000N
Why does a feather and hammer accelerate the same amount in a vacuum but not on outside a vacuum
As mass increases so does the force from gravity on it (weight) meaning gravity accelerates all objects the same amount. They don’t fall the same out of a vacuum as air resistance slows down the feather but in a vacuum there isn’t any air resistance so they fall at the same acceleration
What is and how does terminal velocity work
Terminal velocity is the fastest velocity an object can fall. When an object first falls, its only force is its weight but as it accelerates due to gravity, air resistance starts to reduce its resultant force. When the air resistance becomes equal to the objects weight, the resultant force becomes 0 meaning they are no longer accelerating so the velocity isn’t increasing. This is tithe terminal velocity
What is formula for momentum
Momentum(Kg m/s) = mass(Kg) x velocity (m/s)
What s the formula for for force in terms of momentum
Force(N) = (initial momentum - final momentum)/time (seconds)
What is the formula for work done and letter
Work done = Force x Distance
E = F x D
Joules (J) = Newtons (N) x Meters (M)
Work done = E
What is the formula and letter for power
Power is watts(w) the letter for it is P
Power (W) = work done (J) / time taken (S)
P = E/t
What is the unit and formula for gravitational potential energy
GPE = mass of object (Kg) x gravitational field strength (Kg/N) x vertical height (M)
GPE is measured in joules (J)
GPE = m x g x h
What is the formula and unit for kinetic energy
Kinetic energy = 0.5 x mass (Kg) x velocity squared (m/s)
KE = 0.5 x m x v squared
KE is measured in joules (J)
What is nuclear decay measured in
Becquerels (Bq)
