A particle Q Q\,Q is projected with speed U ms−1U \text{ ms}^{-1}U ms−1 from a point AAA, 30 m above the ground. Q Q\,Q is projected at an angle of 45∘ 45^\circ\,45∘ to the horizontal. B B\,B is the greatest height reached by QQQ, 15 m above AAA.
Find the value of UUU.
Find the horizontal distance travelled.
Find the speed of the particle when it hits the ground.