equations :)

Question 1

density

Answer 1

density (kg/m3) = mass (kg) / volume (m3)

Question 2

distance/speed/time

Answer 2

speed = distance/time
distance = speed x time
time = distance/speed

Question 3

acceleration

Answer 3

acceleration (m/s2) = change in velocity (m/s) / time (s)

Question 4

kinetic energy

Answer 4

kinetic energy (J) = 0.5 x mass (kg) x speed2 (m/s)

Question 5

newton’s second law

Answer 5

force (N) = mass (kg) x acceleration (m/s2)

Question 6

momentum

Answer 6

momentum (kgm/s) = mass (kg) x velocity (m/s)

Question 7

work done

Answer 7

work done (J) = force (N) x distance (m)

Question 8

power

Answer 8

power (W) = work done (J) / time (s)

Question 9

force exerted by spring

Answer 9

force (N) = extension (m) x spring constant (N/m)

Question 10

gravity

Answer 10

gravity force (N) = mass (kg) x gravitational field strength (N/kg)

Question 11

GPE

Answer 11

GPE (J) = mass (kg) x height (m) x gravitational field strength (N/kg)

Question 12

moment of a force

Answer 12

moment (N/m) = force (N) x distance (m)

Question 13

charge flow

Answer 13

charge flow (C) = current (A) x time (s)

Question 14

potential difference

Answer 14

p.d (V) = current (A) x time (s)

Question 15

energy transferred

Answer 15

energy transferred (J) = charge (C) x potential difference (V)

Question 16

wave speed

Answer 16

wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 17

efficiency

Answer 17

efficiency = useful output energy (J) / input energy transfer (J)

Question 18

acceleration due to gravity

Answer 18

10m/s2

Question 19

gravitational field strength

Answer 19

9.8 or 10 N/kg

Question 20

estimate speeds

Answer 20

30 mph = 13 m/s