A jet plane is rising vertically with a velocity of 10 m/s. It has reached a certain height when the pilot drops a coin, which takes 4 sec to hit the ground. Assuming that there is no resistance to the motion of the coin, the height of the place and the velocity of the coin on impact with the ground are:
Choose the correct answer
A) 38.4 m, 28.7 m/s B) 38.4 m, 29.2 m/s C) 26.5 m, 13.5 m/s D) 26.5 m, 28.7 m/s E) 26 m
The coin will move up with the initial velocity of 10 m/s till it comes to rest. Time taken is given by:   0=10âˆ’9.8t   â‡’t=10/9.8 sec.   Time taken to reach the ground from the highest point:   =4âˆ’10/9.8   =29.2/9.8 sec   Velocity of coin on impact   =0+9.8Ã—(29.2/9.8)   =29.2 m/s   If 'h' is the height from which the coin dropped.   Then   29.2^2âˆ’10^2=2Ã—9.8Ã—h   â‡’h = 38.4 m   Answer : 38.4 m, 29.2 m/s
<result>B</result>
A jet plane is rising vertically with a velocity of 10 m/s. It has reached a certain height when the pilot drops a coin, which takes 4 sec to hit the ground. Assuming that there is no resistance to the motion of the coin, the height of the place and the velocity of the coin on impact with the ground are: