1057is it 2√2+1 secs?
A projectile is fired at t=0 with velocity v = 20√2 m/s at an angle of 45° degrees as shown. A wall inclined at the same angle and at a distance of 40 m starts moving towards the projectile at the same time (ie., t=0) with a speed of 20m/s. Find the time at which the ball collides with the the wall.
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7 Answers
71Can't tell for sure. I don't have the answer. I had a similar answer. Do post your solution.
Edit: I'm getting 2(√3-1) s. Strikingly this is very similar to yours i.e, 2(√2-1) s. Either I missed something or you!
21Let the pt. of impact be at a distance x from base of incline.
Therefore height of pt. of impact=x
Now solve for t,
x=20t-g/2*t2
(40+x)40=t
We get t=2(√3-1)(ans)
262i agree with swaraj's answer.
just the application of relative velocity.
relative vel. of projectile w.r.t incline at t=0 is 40i + 20j
71The problem is that this question is from FIITJEE paper and the options that the y have given are like 1,2,3 or 4 sec? Nothing in roots>>
So, from the discussion above, the options are wrong.
