Question

Three stones A, B and C are simultaneously projected from same point with same speed. A is thrown upwards , B is thrown horizontally and C is thrown downwards from a building. When the distance between stone A and C becomes 10 m , then the distance between A and B will be?

Answer 1

For A stone,

 

x1 = ut – 1/2gt^2 …..................(1)

x2 = ut + 1/2gt^2 …..................(2)

x1 + x2 = 10 …..............(3)

solving eqns. (1) (2) and (3)

2ut = 10

t = 5/u …....................................................(4)

 

For stone B,

x3 = ut

from eqn. (4)

x3 = u*5/u = 5

x3 = 5m

 

x1 = u*5/u -(1/2)*g*(25/u^2)

    = 5 – 25g/2u^2

x2 = 5 + 25g/2u^2 

 

Thus distnace between A and B will be:

root(x1^2 + x3^2)

putbthe values and get the answer