how to resolve vector? Explain projectil motion?

Answer 1

You should have learnt that in the class that gave you that homework question.

Answer 2

there are two types of projectile: the vertical projectile which is also known as freefall,,,,, and the other is known as 2 dimesional projectile which has a example of the path made when water is coming out of a nozzle.
for the free fall the fall is usually under the influence of gravity
and in the 2-D projectile the horizontal component of the velocity is zero.
the vertical velocity can be calculated by the formulae: sin of the angle formed = opposite/adjacent
the horizontal velocity can be calculated by the formulae: cos of the angle formed= adjacent/hypotenuse
the height, velocity,time can be calculated by using the three formulaes by newton i.e. vf=vi+at
vf^2=vi^2+as
s=vi(t)+.5(a)(t)^2
the range can be calculated by vertical velocity mulitplied by 2(t)
this is one of the most easiest topics in physics as long as you know what you are looking for and what formulaes to use and why you are using it