1. determine the acceleration of a freely falling object Flashcards
what is meant by free-fall?
an object is said to be in freefall if the only force acting on it is its own weight under gravity. this mean negligible resistive forces are acting on it (small enough to be considered a zero)
what is ‘g’?
gravitational field strength
why can SUVAT be used in the freewill experiment?
since the uniform will fall with uniform acceleration. this is because the force of gravity is approximately constant at the earths surface
when plotting a graph of v^2 against h, how is ‘g’ determined
the gradient of the graph will be v^2/h. consequently the acceleration ‘g’ will be equal to half the gradient. this comes from the equation v^2=u^2-2as
when plotting a graph of t^2 against h, how is ‘g’ determined
the gradient of the graph will be t^2/h. consequently the acceleration ‘g’ will be equal to 2/gradient. this comes from the equation s=ut+0.5at^2
describe how the electro magnet system can be used to determine ‘g’
a magnetic ball bearing can be released by an electromagnetic clamp at a known height. the timing system starts when the electromagnet is switched off, and the timer is stopped when the ball falls on the finish pad
when using a clamp stand what safety precaution should be taken
the clamp sand should have a counter weight or a gclamp attached to its base to provide a moment to prevent it from being knocked over
what safety precaution should be taken when using an electromagnet
they heat up over time so to reduce the heating affect it should be switched off when not in use
why should there be a gap between the release position and the first light gate
to ensure the time of the ball passing through the light gate is negligible
suggest how light gates could e positioned to ensure the the ball or dowel falls directly through them
a plump line could be used to demonstrate the expected path of the object. this allows the light gates to be positioned in appropriate places, so that the ball will fall through them
why is it advantageous to use a small ball bearing instead of a large one
the effect of air resistance is less on a smaller one, therefore the assumption of no other forces on the ball is more valid with a small ball
why would this experiment not be valid if there was air resistance
acceleration would not be purely due to the force of gravity. the acceleration would also be variable as air resistance increases with velocity so Suva can’t be used
why may the value of ‘g; found be inaccurate
-delays in timing equipment (if using a stopwatch then human reaction time)
-resistive forces
-errors in height measures (measuring from different positions on the ball each time)
what are the advantages of using light gates instead of a stopwatch
light gates should result in a lower uncertainty in measurements. using a stopwatch requires human reactions which creates further uncertainties in timing accuracy
how could the results of this experiment be improved
take repeat reading at each height and calculate the mean time taken, for all non-anomalous results. should also ensure that height readings are taken from the same point on the ball each time
