Question

two girls are standing at the ends A and B of a ground where A B=a . The boy at B starts running in a direction perpendicular to A B WITH VELOCITY V1 . The boy at A starts running simultaneously with velocity V AND catches the other boy in a time t, where t is

Answer 1

Answer:

If girl A catches girl B in time t,

⟹(vt)

2

=(v

1

t)

2

+a

2

⟹t

2

=

v

2

−v

1

2

a

2

⟹t=

v

2

−v

1

2

a

Answer 2

Answer:

t = $\frac{a^{2} }{(V^{2}-V_{1}^{2} )}$

Explanation:

Distance covered by boy A in time t ⇒ AC = Vt

Distance covered by boy B in time t ⇒ BC = V₁t

Using Pythagoras Theorem :

⇒ AC² = AB² + BC²

⇒ (Vt)² = a² + (V₁t)²

⇒ a² = V²t² - V₁²t²

⇒ a² = t²(V²-V₁²)

⇒ t² = a²/ (V²-V₁²)

∴ t = $\frac{a^{2} }{(V^{2}-V_{1}^{2} )}$