A Projectile motion problem, I .

[a.ratnaparkhi]

Homework Statement

A cannon fires successively two shells with velocity u=250 m/s;the first at angle $$\theta1$$=$$\pi/3$$ & the second shell at an angle $$\theta2$$=$$\pi/4$$ to the horizontal, the azimuth being same. Neglecting air drag, find the time interval between firings leading to colling of shells.

Homework Equations

range R=(u^2sin2$$\theta$$)/g
Time of flight t=(2usin$$\theta$$)/g

The Attempt at a Solution

I'm really confused &unable to figure out.
Book says that its 11s.

 

[paragchitnis]

Find the horizontal distance where the two bodies collide by solving there equations. From this, you can get time of flight of two bodies from projection to collision and what you need..?

 

[a.ratnaparkhi]

I thought, if we assume the required time interval 't' and time of flight of two shells T1& T2 respectively, then after equating T1+t=T2, 't' can be easily found.

 

[zgozvrm]

I thought, if we assume the required time interval 't' and time of flight of two shells T1& T2 respectively, then after equating T1+t=T2, 't' can be easily found.

No...that would be the time between firings to get the shells to hit the ground simultaneously.