A stone is dropped from a balloon going up with a uniform velocity of 5m/s. If the balloon was 60 m high when the stone was dropped, find the height of balloon when the stone hits the ground. Take g=10m/s.
A
50 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
60 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
80 m
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
100 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is C80 m
Time taken by the stone to reach the ground: s=ut+12at2 ⇒−60=5(t)+12(−10)t2 ⇒−60=5t−5t2 ⇒5t2−5t−60=0 ⇒t2−t−12=0 ⇒t2−4t+3t−12=0 ⇒(t−4)(t+3)=0 ⇒t=4s
Height of balloon from ground at this instant is h=60+(4)(5) ⇒h=80m