# Motion in Two Dimension

1. Apr 30, 2008

### kkumar

In its final trip upstream to its spawning territory, a salmon jumps to the top of a waterfall 1.9m high. What is the minimum vertical velocity neeeded by the salmon to reach the top of the waterfall?

This uestion has no velocity so, do you think that final velocity is Zero.......
solution:

Vfinal y=0m/s
Vfinal X=at as initial velocity for x is 0
dy=1.9m
0=v initial y+2*(-9.8)*1.9
V initial = 37.24m/s

2. Apr 30, 2008

### alphysicist

Hi kkumar,

I believe you have the equation wrong. The velocities are squared, so it is:

$$v_y^2 = v_{oy}^2 + 2 a_y(\Delta y)$$

and so you need to take a square root to get your final answer.

3. May 12, 2008

### kkumar

Thanks for your help in soiving my problem.

4. May 13, 2008

### kkumar

Hello I need help with this question as soon as possible. Can anyone help me out?

1) Consider the frictionless roller coaster. A car 12000kg car starts at rest from point A The height of point A is 95 m and comes down to point B which is at height of 65m and then bounce back again to point C which is at height 65m again and then bounce back to point D which is 25 m from the bottom and then rolls on the floor and stops at a point E.

A) calculate the total energy of the system
B) the speed of the car at point B
C) the force that must be applied to bring it to a stop at point.
D) The work done to bring it to a stop at point E.

5. May 13, 2008

### kkumar

I have worked it out but not sure if it is right.
Thank in advance for working on it

6. Aug 23, 2008

### hardlyfe

hi alphysicist i need ur help with dis ques--> in its final trip upstream to its spawning territory, a salmon jumps to the top of a waterfall 1.9 m high. what is the minimum vertical velocity needed by the salmon to reach the top of the waterfall?

7. Aug 23, 2008

### alphysicist

Hi hardlyfe,

What have you tried so far? What equation have you used, what numbers are you using, and what did you get for an answer?

8. Aug 24, 2008

### hardlyfe

so i tried solving it by ur formula the answer that i got is 6.1 m/s for Viy. but im not sure if dis answer is rit or wrong.......

thnx a lot for replyin ma ques..

9. Aug 24, 2008

### alphysicist

That looks right to me. Does it not seem right to you?

10. Aug 25, 2008

### hardlyfe

thnx anywaz.....