Question

# A particle is projected vertically upwards with speed 20 m/s from top of a tower of height 20 m as shown in figure. Given B is top most point of trajectory and C is at same height as A : Column - IColumn - II(A)ratio of maximum height from ground (BD)(P)1√2to the initial height from ground (AD)is(B)ratio of distance travelled in 1st second to(Q)1√3the distance travelled in 2nd second is(C)ratio of initial speed at A to the final(R)1just before reaching to ground (D) is(D)ratio of time taken from A to C and time(S)2taken from A to B is(T)4(U)3 Which of the following option has the incorrect combination considering column-I and column-II

A
AS
B
BQ
C
CP
D
DS

Solution

## The correct option is B B→Q(I) AB= maximum height =v22g=20×202×10=20 m ∴BDAD=20+2020=2 (II) s(1st)s(2nd)=20×1−12×10×1220−[15]=155=3 (III) vAvD=20√202+2×10×20=2020√2=1√2 (IV) tACtAB=2tABtAB=2

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