Question

A rocket is launched upward from the earth surface whose velocity time graph is shown in fig.then maximum height attained by the rocket

Answer 1

Answer: option (4) 60km

Step-by-step explanation:

   here graph is given,

maximum height is attained by rocket = area enclosed by part of graph which is above the x - axis.

              = area of triangle OAB

              = 1/2 * OB * altitude AT

 

             = 1/2 × 120 seconds × 1000 m/s

             

              = 60 × 1000 m = 60 km

hence, height attained by rocket is 60km

[ note : rocket starts from rest and moves upwards with increasing speed at 20sec , after 20sec rocket decreases its speed continuously, at point B e.g., t = 120 sec speed of rocket becomes zero. so, now rocket starts to fall downwards. but question asked we have to find maximum height attained by rocket , so just require to find the distance travelled by rocket unless it becomes rest in upward motion,e.g, t = 120sec . that’s why we find area enclosed by graph at point B. ]