Units and formulas

Question 1

What is the unit for charge and what is its letter

Answer 1

Coulombs (Q in formula, C when written)

Coulombs = time x amps

Question 2

What is the unit for currant and what is its letter

Answer 2

Amps (I in formula A when written)

Amps = coulombs / time

Question 3

What is t

Answer 3

Time (seconds)

Question 4

What is The unit for the difference in energy across a component in a circuit

Answer 4

Potential difference / volts (V in formula and written)

Question 5

What is the unit for energy

Answer 5

Joules and written as (J)

Joules = currant (amps) X potential difference (volts) X time (seconds)

Question 6

What is unit for resistance in a circuit

Answer 6

Ohms

Question 7

What is the formula of potential difference

Answer 7

V = I x R

Potential difference = currant (amps) X resistance (ohms)

Question 8

What is unit and formula of power

Answer 8

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

Question 9

Formula for speed

Answer 9

Speed(m/s) = distance(m) / time taken (s)

Question 10

What is sign and formula of acceleration

Answer 10

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

Question 11

What is force measured in

Answer 11

Newtons (N)

Question 12

Formula of resultant force

Answer 12

Larger force - smaller force

Question 13

What happens if the resultant force is 0 and what happens if the resultant force is greater than 0

Answer 13

If it is 0, the velocity will stay constant, if it is greater than 0, it will accelerate in the direction of the force.

Question 14

What does acceleration depend on

Answer 14

The size on the resultant force and the mass of the object.

Question 15

What s the formula for force needed to accelerate an object

Answer 15

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

Question 16

Unit for gravitational field strength

Answer 16

N/Kg

Question 17

What is the formula for weight

Answer 17

Weight(N) = mass(Kg) X gravitational field strength (N/Kg)
W = m x g

Question 18

What is the weight of a 300Kg landing craft on earth

Answer 18

W = m x g
W = 300Kg x 10N/Kg
W = 3000N

Question 19

Why does a feather and hammer accelerate the same amount in a vacuum but not on outside a vacuum

Answer 19

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

Question 20

What is and how does terminal velocity work

Answer 20

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

Question 21

What is formula for momentum

Answer 21

Momentum(Kg m/s) = mass(Kg) x velocity (m/s)

Question 22

What s the formula for for force in terms of momentum

Answer 22

Force(N) = (initial momentum - final momentum)/time (seconds)

Question 23

What is the formula for work done and letter

Answer 23

Work done = Force x Distance
E = F x D
Joules (J) = Newtons (N) x Meters (M)
Work done = E

Question 24

What is the formula and letter for power

Answer 24

Power is watts(w) the letter for it is P
Power (W) = work done (J) / time taken (S)
P = E/t

Question 25

What is the unit and formula for gravitational potential energy

Answer 25

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

Question 26

What is the formula and unit for kinetic energy

Answer 26

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)

Question 27

What is nuclear decay measured in

Answer 27

Becquerels (Bq)