Practise Edexcel A-Level Physics graph relationships by testing proportional models, gradients and transformed equations.
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.