Question

A projectile is given an initial velocity of (i+2 J) m/s, where i is along the ground and j is along the vertical. If g = 10 m/s², the equation of its trajectory is

(a) y = x - 5x²

(b)  y =  2x - 5x²

(c) 4y = 2x - 5x²

(d) 4y = 2x - 25x²

Answer 1

Correct option (b)  y =  2x - 5x²
Explanation :

As, initial velocity v =(i + 2 j) m/s
For projectile
Motion along horizontal direction,

x = t ...(i)

Motion along vertical direction,

y = ut - 1/2 gt²

where, u is a vertical component of velocity.

y = 2t - 1/2 10t^{2   ....(ii)}

From Eqs. (i) and (ii), we get

y = 2x - 5x²