Question

A body is projected horizontally from a point above the ground and motion of the body is described by the equation $x=2t,y=5t^2$ where $x,$ and $y$ are horizontal and vertical coordinates in meter after time $t$. The initial velocity of the body will be

• A. $\sqrt{29}m/s$ horizontal
• B. $5m/s$ horizontal
• C. $2m/s$ vertical
• D. $2m/s$ horizontal

Answer 1

The correct option is D $2m/s$ horizontal

The horizontal velocity of projectile remains constant throughout the journey.
Since the body is projected horizontally, the initial velocity will be same as horizontal velocity at any point.
Since, $x=2t,\frac{dx}{dt}=2$

$\therefore$ Horizontal velocity$=2m/s$
Initial velocity $=2m/s$