Question

A stone lying at the edge of road falls down into a river below the road if stone takes is to reach the river then find the speed with which stone striker the water surface in the river. Also calculate the average speed of stone of the end of fall. Highly of the rood from the river $g=\left(10\right)$

Answer 1

According to the question , $u=0,a=10\frac{m}{s^2},t=1s$ and we have to find $v,v_{av}ands$

for finding $v$ we use first equation of motion :$v=u+at$

this gives speed with which stone strikes water , $v=0+10\times 1=10\frac{m}{s}$

Now,$v_{av}=\frac{u+v}{2}=\frac{10}{2}=5\frac{m}{s}$

and for displacement we use 2nd equation of motion :$s=ut+\frac{1}{2}a{t}^2$

this gives height of road from the river as, $s=0+\frac{1}{2}\times 10\times 1^2=5m$