4. A pan of water is heated from 23°C tą 78°C. What is the change in its temperature on the Kelvin and Fahrenheit scales?

ice to water 1 water to vapour 2 latent heat

the area between the graph and the t axis

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.