formulae

Question 1

avg speed formula

Answer 1

avg speed = distance moved / time taken

Question 2

final velocity formula

Answer 2

v² = u² + 2as

v = final velocity
u = initial velocity
s = distance travelled while accelerating
a = acceleration

formula only works when acceleration is constant

Question 2

acceleration formula

Answer 2

acceleration = change in velocity/ time taken

(v-u)/t

(a negative value means deceleration - slowing down)

formula only works when acceleration is constant

Question 3

weight formula

Answer 3

weight = mass x gravitational strength

w = mxg

Question 4

Force (N)

Answer 4

mass (kg) x acceleration (m/s^2)
F=ma

Question 5

stopping distance

Answer 5

thinking d + braking d

Question 6

voltage

Answer 6

current x ressistance
V = IR

Question 7

charge (C)

Answer 7

current x time
Q= It

Question 8

energy transfered (J)

Answer 8

charge x voltage
E =QV

or

charge x current x ressistance
E = QIR

Question 9

electrical power (w)

Answer 9

current x voltage
P=IV

Question 10

energy transfered (electrial appliances)

Answer 10

current x voltage x time
E = IVt

Question 11

wave speed (m/s)

Answer 11

freq (Hz) x wavelength (m)
v = f x λ

Question 12

angle of incidence

Answer 12

= angle of reflection

Question 13

refractive index

Answer 13

speed of light in a vaccum/ speed of light in materical

n = c/v

Question 14

snells law

Answer 14

refractive index (n) = sin i / sin r

Question 15

snell and critical angles

Answer 15

sin C = 1/n

Question 16

efficiency

Answer 16

useful energy output/ total energy output x 100

Question 17

work done (J)

Answer 17

force (n) x distance moved (m)
W=Fd

Question 18

power

Answer 18

work done / time taken

Question 19

energy in kinetic energy store

Answer 19

1/2 x mass x speed²
1/2 x m x v²

Question 20

energy in gravitational potwntial energy store

Answer 20

mass x gravitational field strength x height