# physics lab report

Extracts from this document...

Introduction

Aim

to determine the acceleration of free fall in the Friends Boys school in El-Bireh using photogates.

Data Collection

Table(1): showing the time needed for the sphere to fall from given heights.

Trial | Height h/cm (±0.5cm) | Time t/ms (±0.5ms) |

1 | 10.0 | 155 |

2 | 20.0 | 212 |

3 | 30.0 | 256 |

4 | 40.0 | 293 |

5 | 50.0 | 326 |

6 | 60.0 | 353 |

7 | 70.0 | 385 |

8 | 80.0 | 411 |

9 | 90.0 | 434 |

Data Processing and Presentation

Conversion factors

1 millisecond = 10ˉ³ second

1 centimetre = 10ˉ² metre

Table (2): showing the time and the time² needed

Middle

0.600

0.353

0.124

7

0.700

0.385

0.147

8

0.800

0.411

0.169

9

0.900

0.434

0.188

Nadeem Rabaia

1. Absolute error in time²

Absolute error in time²( ∆t²) = (absolute error in time (∆t) + absolute error in time (∆t)) * time²(t2)

time(t) time(t)

∆t² = ( ∆t + ∆t)*t²

t

∆t² = ( 2∆t)*t²

t

∆t² = 2(0.0005) (0.0655) = 0.0003s

0.256

2. Acceleration of free fall

d=h= ut + ½at²

a=g = acceleration of free fall (constant)

Variables:

d=h=the distance between the upper photogate and the lower photogate

u=initial velocity of the sphere (we assume it is equal to 0ms-1)

t=the time taken for the sphere to fall from the height

Figure 1: the apparatus used in the experiment.

h= (0)t + ½(g)t²

h= ½gt2

Slope(m) of the graph of h vs. t2 = ½(g) =∆y = y2-y1 = 0.800-0.500 = 4.76ms-2

∆x x2-x1 0.169-0.106

g= 9.52ms-2

graph is on graph paper.

3.

Conclusion

Improvements

- Using apparatus that will start timing when object is dropped and will stop timing when the object strikes a sensor below or passes a photogate. This might give more accurate results as the initial velocity of the sphere would 0msˉ¹.

- Using a more accurate time measuring device and more accurate distance measuring equipment.

- Making sure that the metre is viewed at right angles to overcome parallax error.

- Conducting the experiment in a vacuum box to reduce the effects of air resistance on the metal sphere.

This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.

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