In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A particle P P\,P is projected with velocity (3i+4j)(3\mathbf{i} + 4\mathbf{j})(3i+4j) m s−1^{-1}−1 from a point 20 m above horizontal ground, where i\mathbf{i}i is horizontal and j\mathbf{j}j is vertically upwards. Air resistance is modelled as negligible.
Find the speed of P P\,P after 2 seconds.
Find the greatest height of P P\,P above the ground.