Practise Edexcel A-Level Physics processing-results skills through processed columns, graph plotting, gradient constants, percentage uncertainty and consistency checks.
A student investigated the bending of a plastic beam.
The beam, of width w and height h, was supported at either end by two metal rods a distance l apart, as shown.
She applied a force F to the middle of the plastic beam by hanging a mass from it.
The beam bent downwards as shown.
She measured the vertical distance d moved by the middle of the plastic beam and repeated this measurement for increasing values of F.
She recorded her results in a table, as shown.
Using the grid opposite, plot a graph of d on the y-axis against F on the x-axis.
Determine the gradient of your graph.
Gradient =
The student recorded the following measurements for the plastic beam.
l / cm = 30
w / mm = 20
h / mm = 10
Determine E, in GPa, for the plastic beam.
E = GPa
Concrete is often used to make supporting beams in buildings.
Strands of a material can be added to the concrete mix to produce fibre-reinforced concrete.
A student had some small beams made of fibre-reinforced concrete.
Each beam was the same size.
He placed a beam across two supports, as shown.
The student repeated the experiment using beams that contained different masses of reinforcing fibres. The student's results are shown in the table.
The student concluded that the increase in maximum force was proportional to the mass of fibre in the beam.
Explain how the student could justify his conclusion.