Question

A stone is thrown upwards with a velocity of 72 km/h. If air resistance is
neglected, find the maximum height travelled by it and the time taken for it to
return to the initial position.​

Answer 1

Answer:

converting speed into m/s =72*5/18=20 m/s

v^2=2gh

20*20=2*10*h

h=20m (maximum height)

v=gt

20=10*t

t= 2s time for upward motion

totaol time(upward+downward)=2+2=4s

Answer 2

Answer:

soln

Explanation:

speed(v)=72km/h

              =72*1000m/60*60s{to convert in meter per second}

               =20m/s

now

      v^2=2gh

       (20)^2=2*10*h

       400=20h

        h=20m

again

        v=gt

        20=10*t

         t=2s{only upward motion}

so

   total time(upward+downward)= 2s+2s

                                                      = 4s