A body is projected from origin such that its position vector varies with time as r=3ti+4t-5t2j^m and t is time in second. Then,

Comparing with projectile motion,r=uxti^+uyt-12gt2j^We have, ux=3 m/s,uy=4 m/sand g=10 m/s2T=2uyg=0.8 s(a) R=uxT=2.4 m(b) u=ux2+uy2=5 m/s(c) θ=tan-1uyux=tan-143(d) T=0.8 s