projectiles

[woeful bane]

Not sure how to go about c (without energy equation).

also how to do c of this question:

[lone cape]

First we must consider the vertical motion,using suvat we know the displacement (from rest to point R)
is -36 the vertical initial velocity (40sin22.5) and acceleration as -g.
Using suvat find final velocity.
We must also consider the horizontal velocity which remains at 40cos22.5.As velocity is a vector quantity we must find it’s magnitude by applying Pythagoras. V=sqrt(hz component of velocity +final vt component of velocity)

[lone cape]

This is just s=ut+1/2at^2 forming a quadratic and taking the positive solution