# Kinematics in Two Dimension

1. Sep 6, 2008

### pstfleur

1. Two planes are each about to drop an empty fuel tank. At the moment of release each plane has the same speed of 135 m/s, and each tank is at the same height of 2.00 km above the ground. Although the speeds are the same, the velocities are different at the instant of release, because one plane is flying at an angle of 15 degrees above the horizontal and the other is flying a an angle of 15 degrees below the horizontal. Find the magnitude and direction of the velocity with which the fuel tank hits the ground if it is from (a)Plan A and (b) Plane B. in each part, give the directional angles with respect to the horizontal.

Vf=Vo-gt, vf^2=Vo^2-2g(delta y), yf=Yo+vot-1/2gt^2

3. This problem looks so complex,
I can't really find the x and y components of the angle because i am not given the initial velocity of either plane(or so i think). Can Someone please guide me in the right direction with this problem

2. Sep 6, 2008

### chislam

It says that the "at the moment of release each plane has the same speed of 135 m/s", as well as their angles above/below the horizontal; therefore, you have your initial velocity. Split this into your x and y components. I'll give you a small hint too: Remember the symmetry of a parabola because it'll cut this problem in half.

3. Sep 6, 2008

### pstfleur

K, I don't know about the symmetry of a parabola.. but to refer to your first half, if i find the x and y component of the speed and angle, that means that it is the initial velocity of both planes, but later in the problem it says "although the speeds are the same, the velocities are different at the instant of release" ...?

4. Sep 6, 2008

hello? lol

5. Sep 7, 2008

### Redbelly98

Staff Emeritus
The speeds are the same. But they are going in different directions, hence different velocity.

Remember, velocity is determined by speed and direction.

6. Sep 7, 2008

### chislam

Well about the symmetry, just work out the whole problem and afterwards you will probably notice what I meant.