A particle starts from origin t=0 with a velocity 5.0 ^i m/s and moves in x-y plane under action of a force which produces a constant acceleration of (3.0 ^i + 2.0^j) m/s squ.
a) What is the y coordinate of the particle at the instant its x coordinate is 84m?
b)What is the speed of the particle at this time?
Please help! :o