Find the magnitude of the velocity vector on impact

[ilovedeathcab]

(resolved) find the magnitude of the velocity vector on impact

Thelma and Louise drive their '66 T-Bird convertible off a cliff. They are going 25.9 m/s and the cliff is 97 meters high. Find the magnitude of their velocity vector the moment they impact the ground. Make sure you do the following in your answer:

DO NOT include units. We'll deal with that in the next question.
Give precision to tenths (#.#).
Make your answer correct to within 0.2

so given y is -97, and vi is 25.9 m/s


equations for horizontal projectile motion for vf are
vyf=-g(t)
vf=sqrt of (vxf^2+vyf^2)
so far for t i had 4.447seconds

____
\/-2*-97
----------= 4.447
9.81
and had vyf as -44.6m/s

 

[mgb_phys]

You don't need the time.
You can use vf² = vi² + 2as for the vertical velocity
Since you ignore air resistance there is no change in the horizontal velocity.

 

[merryjman]

And think of vxf and vyf as being two legs of a right triangle. The answer you're looking for is the hypotenuse of this triangle.

 

[ilovedeathcab]

You don't need the time.
You can use vf² = vi² + 2as for the vertical velocity
Since you ignore air resistance there is no change in the horizontal velocity.

what is 2as?

 

[mgb_phys]

2 * acceleration * distance
It's one of the standard motion equations - although some books use different letters.