Find the magnitude of the velocity vector on impact

  • #1
(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
 
Last edited:

Answers and Replies

  • #2
mgb_phys
Science Advisor
Homework Helper
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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.
 
  • #3
183
0
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.
 
  • #4
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????
 
  • #5
mgb_phys
Science Advisor
Homework Helper
7,774
13
2 * acceleration * distance
It's one of the standard motion equations - although some books use different letters.
 

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