Q.
A elevator car whose floor to distance is 2.7m starts ascending with a constant acceleration of 1.2m/s2,2 s after a bolt is begin to fall from the ceiling of the car. The free fall time of the bolt is (g=9.8m/se)
1939
207
ManipalManipal 2013Motion in a Straight Line
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Solution:
Net acceleration on the elevator car is more than acceleration due to gravity.
Since elevator car is ascending upwards, from Newtons second
law, the net force is acting upwards hence resultant acceleration is ar=(g+a) =(9.8+1.2)=11m/s2
Relative velocity of observer to elevator is ur=0
from the equation s=urt+21a,t2 2.7=0+21×11×t2 t2=115.4 t=115.4s