[2009] In an experiment to measure the acceleration due to gravity, the time for an object to fall from rest through a distance t was measured. The procedure was repeated for a series of values of the distance The table shows the recorded s s. data. cm 30 50 70 90 110 130 150 s/ 247 310 377 435 473 514 540 t/ms Draw a labelled diagram of the apparatus used in the experiment. Indicate the distance on your diagram. s Describe how the time interval was measured. t Calculate a value for the acceleration due to gravity by drawing a suitable graph based on the recorded data. Give two ways of minimising the effect of air resistance in the experiment. [2004] In an experiment to measure the acceleration due to gravity by a free fall method, a student measured the time g t for an object to fall from rest through a distance s. This procedure was repeated for a series of values of the distance s. The table shows the data recorded by the student. 30 40 50 60 70 80 90 s/cm 244 291 325 342 371 409 420 t/ms Describe, with the aid of a diagram, how the student obtained the data. Calculate a value for by drawing a suitable graph. g Give two precautions that should be taken to ensure a more accurate result. Exam solutions Velocity is the rate of change of displacement with respect to time. Acceleration is the rate of change of velocity with respect to time. v = u + at a = ( v u ) ÷ t a = (30 10) ÷ 5 a = 4 m s-2. – – v = u + at 0 = 60 + a (120) a = - 0.5 m s-2   See diagram v = u + at 28 = 0 + a (4) a = 7 m s-2 See diagram Distance (s) = area under curve s = ½ (3)(9.2) + 2 (9.2) / 13.8 + 18.4 / 32.2 m 12 m s-1. v = u + at but u = 0 a = v/t = 20/10 = 2 m s-2.  v = s/t s = vt = 20 × 5 = 100 m 
[2009] s/ cm 30 50 70 90 110 130 150 t/ms 247 310 377 435 473 514 540 In an experiment to measure the acceleration due to gravity, the time t for an object to fall from rest through a distance s was measured. The procedure was repeated for a series of values of the distance s. The table shows the recorded data. Draw a labelled diagram of the apparatus used in the experiment. Indicate the distance s on your diagram. Describe how the time interval t was measured. Calculate a value for the acceleration due to gravity by drawing a suitable graph based on the recorded data. Give two ways of minimising the effect of air resistance in the experiment. [2004] In an experiment to measure the acceleration due to gravity g by a free fall method, a student measured the time t for an object to fall from rest through a distance s. This procedure was repeated for a series of values of the distance s. The table shows the data recorded by the student. s/cm 30 40 50 60 70 80 90 t/ms 244 291 325 342 371 409 420 Describe, with the aid of a diagram, how the student obtained the data. Calculate a value for g by drawing a suitable graph. Give two precautions that should be taken to ensure a more accurate result. Exam solutions Velocity is the rate of change of displacement with respect to time. Acceleration is the rate of change of velocity with respect to time. v = u + at a = ( v – u ) ÷ t a = (30 – 10) ÷ 5 a = 4 m s-2. v = u + at  0 = 60 + a (120)  a = - 0.5 m s-2 See diagram v = u + at 28 = 0 + a (4) a = 7 m s-2 See diagram Distance (s) = area under curve s = ½ (3)(9.2) + 2 (9.2) / 13.8 + 18.4 / 32.2 m 12 m s-1. v = u + at but u = 0  a = v/t = 20/10 = 2 m s-2. v = s/t  s = vt = 20 × 5 = 100 m
7.%20Acceleration.docx