IIT JEE , AIEEE Forum - Physics , Mechanics

shubham.123

a cannon shell is fired to hit target at horizontal distance R .

IT BREAKS into two parts at highest point .

one parts return to cannon .

prove the other part will fall at distance R beyond target......

rooney

Let vel at highest point be V.
Let mass of each part be m. So, total mass is 2m.
Conserving momentum along horizontal,
2mv = -mv + mV

So, V = 3v.
Now , 3v = v + 2v. v will take it till the target (R/2 Horizontal distance) and 2v will take it R forward (2xR/2 = R). Time taken by both parts to reach ground is same

Another way is.. since 2nd part has 3times the velocity of the 1st part it will travel 3 times the distance which is 3xR/2 = 3R/2. which is obviously R forward than target.

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