Isaac physics question A5.4

https://isaacphysics.org/questions/phys19_a5_q4?board=phys19_a5&stage=a_level - its part b i can't figure out

They've given you a 'politicians graph' which shows an arbitrary section of the full picture

But it's asking you to extrapolate to the point where one of the variables is zero.

Reply 2

Eimmanuel

Study Forum Helper

Original post by lily.mason

https://isaacphysics.org/questions/phys19_a5_q4?board=phys19_a5&stage=a_level - its part b i can't figure out

Welcome to TSR! :smile:

There are "two ways" of attempting the question. In fact, they are essentially the same thing.
First way, use the gradient that you have found in part A.
At the y-intercept, the point is (0, c), where c is the y-intercept. Hope you know why.
Then you can pick another point on the straight line. Use the gradient formula to find c.

The second way is to write the equation of the straight line: y = mx + c, where m is the gradient and c is the y-intercept.
Again pick a point from the straight line and sub into the equation y = mx + c to find c.