## anonymous 3 years ago Minimum velocity of a projectile is 20 m/s when a body is projected at an angle of 60 degree with the horizontal .Find the vel of projection....20 m/s,10 m/s,30 m/s or 40 m/s?

1. anonymous

so you want the horizontal velocity?

2. anonymous

The question i have posted verbatim from my daughter's weekly test. I am not sure but there must be some conditionalities for 20 m/s to be the minimum velocity ..

3. anonymous

and there is no diagram or anything?

4. anonymous

No none. Only 4 options as I noted above.

5. anonymous

it doesnt even have the word "the" at the start of the sentence? Perhaps she copied the question down wrong?

6. anonymous

My mistake it should read "The Minimum.. I have the question paper right in front of me..

7. anonymous

and it just gives "find the vel of projection"?

8. anonymous

It reads " The Minimum.....with the horizontal. The velocity of projection is 1) 20 m/s 2) 10 m/s 3) 30 m/s 4) 40 m/s "

9. anonymous

RIGHTTT thats much better. so the minimum velocity is 20m/s in the horizontal direction. find the absolute velocity. okay so i think it looks like this

10. anonymous

|dw:1350148494782:dw| your trying to find the hypotenuse

11. anonymous

12. anonymous

Her text book says there is a minimum velocity of projection to reach a specific point .I am not very satisfied taking 20 m/s as the vel in the horizontal direction. It should have been 20 Cos 60 as the horizontal component as it remains constant..is there any other possibility?

13. anonymous

wel in this isntance ? = 40 m/s

14. anonymous

what is the specific point?

15. anonymous

How did you deduce? Pl help as I need to understand & then teach my daughter.

16. anonymous

Well I just found the hypotenuse of that triangle $velocity = hypotenuse = \frac{20 m /s}{\cos (60)} = 40 m/s$