Kinematics Question 222
Question: A body thrown vertically upwards with an initial velocity $ u $ reaches maximum height in 6 seconds. The ratio of the distances travelled by the body in the first second and the seventh second is [EAMCET (Engg.) 2000]
Options:
A) 1 : 1
B) 11 : 1
C) 1 : 2
D) 1 : 11
Show Answer
Answer:
Correct Answer: B
Solution:
Time of ascent $ =\frac{u}{g}=6\ \sec \Rightarrow u=60\ m/s $
distance in first second $ {h _{first}}=60-\frac{g}{2}(2\times 1-1)=55\ m $
distance in seventh second will be equal to the distance in first second of vertical downward motion $ {h _{seventh}}=\frac{g}{2}(2\times 1-1)=5\ m $
therefore $ {h _{first}}/{h _{seventh}} $
$ =11:1 $
