## A community for students. Sign up today

Here's the question you clicked on:

## idku one year ago Please help me with 2 brief questions.

• This Question is Closed
1. idku

A cannonball is shot (from ground level) with an initial horizontal velocity of 33 m/s and an initial vertical velocity of 25 m/s. ------------------------------------------------------------ $$\rm \large I~found~so~far:$$ [1] initial speed, $$\rm u=41.4(m/s)$$ [2] angle of cannonball with respect to ground, $$\rm \theta=37.15º$$ [3] maximum height the cannonball goes above the ground $$\rm x=31.8(m)$$ [4] horizontal displacement is $$\rm 167.6(m)$$ [5] the entire time of the ball motion $$\rm 5.1(s)$$ ------------------------------------------------- $$\rm \large I~need:$$ [6] speed of the cannonball at, $$\rm t=3.7(s)$$ [7] height (Vertical Displacement) at, $$\rm t=3.7(s)$$

2. anonymous

6.Vi = √[Vx²+Vy²] = 44.2 m/s 7.3) Hmax = Vi²sin²Θ/(2g) = 62.49 m

3. idku

Are you sure? Becsause that doesn't seem to be right.

4. anonymous

Don't know,I never liked physics. Maybe he can help @Hero @dan815 @iambatman

5. anonymous

@triciaal

6. idku

I found the vertical displacement x=25.35m applying: $$x = ut + \dfrac{1}{2}at^2$$ I have put: t=3.7s a=-9.81m/s$$^2$$ u=25m/s

7. anonymous

Nice.

8. idku

I need velocity at t=3.7 the rest i found. tnx for coming btw

9. anonymous

Your welcome!

10. dan815

A cannonball is shot (from ground level) with an initial horizontal velocity of 33 m/s and an initial vertical velocity of 25 m/s. [6] speed of the cannonball at, t=3.7(s) [7] height (Vertical Displacement) at, t=3.7(s)

11. idku

[7]=25.35m found that:)

12. dan815

|dw:1441344582144:dw|

13. dan815

speed is the magnitude of velocity

14. dan815

velocity tells you how speed is broken into components of direction

15. idku

$$\large V_y=25-9.81(3.7)=-11.297$$ $$\large V_x=33$$ (yes, it doesn't change b/c acceleration is 0) $$\large V_t=\sqrt{33^2+11.297^2}=34.88$$

16. dan815

yeah

17. dan815

|dw:1441344791089:dw|

18. idku

oh, that is what I wanted to do. to use pythagorean theoream after fiding vert and horiz velocities (well horiz veloc I knew...:D) I was getting NEGATIVE 11.297 so I was thinking it is wrong.

19. idku

I mean those veloc at t=3.7

20. dan815

negative velocity just means down, it an indication of direction thats all

21. idku

I will take a note of that in my brain. Ok, so negative velocity is also an acceptable result (unlike displacement)

22. dan815

to someone who flipped the page, he will think the Veocity is positive it doesnt matter to him its the way u chose your coordinates

23. idku

I want to flip the page, but another page. The page of the physics intersecting w/ my life.... I don';t even know what I would do without you

24. dan815

LOL

25. dan815

get used to it, uve intersected with physics from the day u were born

26. idku

yes, but not with due dates

27. idku

and not with rediculous teachers such as my prof at college

28. dan815

xD

29. idku

In any case, I guess - Alright. I have a report on a lab. That I should be able to do. (Got 6 hours to work on it before my next classes)

30. idku

Have a good night or where ever yo are. Niagara falls:D

#### Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy