Question

how high does a rock rise in the air if it is thrown upward at an initial velocity 48.3ft/s and if its time of ascent is 1.5s?

Answer 1

here we know that rock is thrown in air with speed

$v_i = 48.3 ft/s$

here we will convert it into SI unit

$v_i = 48.3 * \frac{0.3048}{1} = 14.7 m/s$

now as the rock will rise in the air its velocity will keep on decreasing due to the gravity of earth in opposite direction

here we can say that at the highest point from the earth the speed of the rock will become zero

so we can use kinematics to find the rise of the rock in given time of 1.5 s

$h = \frac{v_f + v_i}{2}*t$

$h = \frac{0 + 14.7}{2}* 1.5$

$h = 11 m$

so the rock will rise up by total height h = 11 m