Rearranging equations

Equations in Science You will receive an equation sheet in your exam containing certain equations. One the next two slides you can see the equations you will be given in the exam for both combined sciences and separate sciences. All other equations have to be learnt for the exams. You will be given questions where you have to rearrange the equations to calculate the answers.

Combined Sciences equation sheet

Separate sciences equation sheet

Rearranging Equations

Practice rearranging the formula

Rearranging in Physics exam questions Mass = 250kg Work done = 5000J Gravitational field strength = 10N/kg You have to calculate weight. You would use the equation weight = mass x gravitational strength Weight = 250 x 10 = 2500N To find height lifted you can use work done = force x distance (or GPE = m x g x h). You need to rearrange the equation to find the distance. W = F x d therefore 𝑊 𝐹 =𝑑 5000 / 2500 = 2m

mass x g x height = 𝟏 𝟐 ×𝒎𝒂𝒔𝒔× 𝒔𝒑𝒆𝒆𝒅 𝟐 GPE = m x g x h KE = 1 2 ×𝑚× 𝑣 2 Mass = 0.5kg Speed = 15m/s Gravitational field strength = 10N/kg It tells us that the potential energy (GPE) changes into kinetic energy (KE). So the GPE at the top of the cliff will equal the KE at the bottom. So we can write; mass x g x height = 𝟏 𝟐 ×𝒎𝒂𝒔𝒔× 𝒔𝒑𝒆𝒆𝒅 𝟐 We need to rearrange the equation to find the height. You will probably find it easier to put the numbers in which you know, to simply the equation before rearranging. 0.5 x 10 x h = 𝟏 𝟐 ×𝟎.𝟓× 𝟏𝟓 𝟐 5 x h = 56.25 Now it is much easier to rearrange h = 56.25 / 5 = 11.25m

Now try some questions….. These are past exam questions The answers are shown on the slide after the question