That’s a pretty big hint that you’re going to have to use that 60° angle to calculate some horizontal and vertical components.

So, let’s get started with solving (a):

They’re asking us for the maximum height reached by the stone. At max height, the velocity is always zero. So, we can say that our final velocity v, in this case, is going to be equal to zero. Hmm, let’s keep thinking. What other variables do we know? Well, we know that we’re throwing a stone upwards, against gravity. So our acceleration is just going to be the opposite of when a stone is thrown downwards. Hence it can be said that acceleration, a, = -10 m/s^2.

So we know a, we know final velocity v, and we’re solving for s (max height). This Suvat equation comes to mind: