Question

A body thrown 2s falls under gravity.what is the velocity of the body when it reaches ground?

Answer 1

Question 31217

The body moves two seconds without initial velocity. The speed at moment $t$ is in general $v(t) = v_0 + gt$, where $v_0$ is the initial velocity (If body moves vertically, according to gravity it gets acceleration $g = 9.81\frac{m}{s^2}$). Since the initial velocity of body is zero, using last formula, for moment of time $t = 2$, obtain $v(2) = g\frac{m}{s^2} \cdot 2s = 9.81\frac{m}{s^2} \cdot 2s = 19.62m$. Hence, the height is $19.62m$.