# A body is projected vertically with speed 10 and other at same time with same speed in downward direction from top of a tower.the magnitude of the accelaration of 1st body w.r.t 2nd body is what??

Kuldeep Pal
53 Points
8 years ago
Zero:

As the motion is only in 1-Dimension so,There is no need for vecor sign. WE can assume as +se as vertical direction And -ve  as downwars Direction.
a(relative)= a1-a2
according to our convention vertical motion is +ve and downward motion is -ve.
So. a1=+g
a2=-g
Hence ,
a(relative) = a1-a2
=(+g)-(-g)
=g-g
=0.

Raman Mishra
67 Points
8 years ago
Dear Taniya, no need to fret. This is a very simple question used for confusing the students. Since the acceleration of both the bodies will be g downwards, therefore their relative acceleration will be zero.
Taking upward direction to be positive and ground as refrence, we have:
Acceleration of 1st body = a1 = -g
Acceleration of 2nd body = a2 = -g
$\dpi{80} \therefore$ Acceleration of 1st body wrt 2nd is given by:
a12 = a1 – a2 = -g – (-g) = 0