Yr10 GCSE PHYSICS FORMULAE YOU NEED TO KNOW:    MARCH 2017

1.    efficiency = useful energy transferred / total energy supplied,                  ɛ = useful energy / total energy           

    (no unit)         (J) / (J)

2. wave velocity = frequency X wavelength,                                                                                    v = f λ        

             (m/s)          (hertz, Hz)     (metre, m)

3. frequency = 1 / time period,                                                                                                        f = 1 / T            

           (Hz)                    (s)

4. force exerted on a spring  = spring constant X extension                                                           F = kx 

        (N)                                           (N/m)                 (m)

5. energy transferred in stretching = 0.5 X spring constant X (extension)2                                  E = ½ kx2  

               (J)                                                      (N/m)                   (m2)

6. heat energy supplied(or lost) = mass X specific heat capacity X change in temperature    ΔQ = m c (Ɵ2  Ɵ1)   

                   (J)                                 (kg)              (J / kg 0C)                            (0C)

7. heat energy for change of state = mass X specific latent heat                                                      Q = mL    

                      (J)                                 (kg)               (J/kg)

  8. average speed = distance / time,                                                                                                v = d / t  

             (m/s)               (m)         (s)

9.acceleration = change in velocity / time taken for change,                                                      a = v – u / t                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      (m / s2)                (m / s)                (s)

      10. (final velocity)2  = (initial velocity)2  +  2 X acceleration X distance moved                         v2 = u2  +  2as                                                                                                                                                                                                     

11.  Force = mass X acceleration,                                                                                                   F = ma    

 (N)        ( kg)          (m/s²)

12. Weight = mass X gravitational field strength,                                                                             W = mg

          (N)          (kg)            (N/ kg)

13. momentum = mass X velocity,                                                                                                    p = mv 

         (kg m/s)       (kg)       (m/s)

14. Force = change in momentum / time,                                                                               F = (mv - mu) / t

        (N)               (kg m/s)                (s)

  15. Work done = Force X distance moved in direction of force,                                                   E = F x d  

              (J)               (N)                    (m)

16. Power = work done or energy transferred / time taken,                                                          P = E / t

         (W)             (J)                                               (s)

17. change in gravitational potential energy = weight X change in vertical height,                      GPE = mgh

                    (J)                                                    (N)                    (m)

18. kinetic energy = ½ X mass X velocity²,                                                                                   KE = ½ mv²    

           (J)                         (kg)        (m/s)²

19. charge = current X time,                                                                                                               Q = It    

  (coulomb, C) (ampere, A) (second, s)

20. Voltage = current X resistance,                                                                                                    V = IR

    (volt, V)   (ampere, A)  (ohm, Ω)