physics
posted by penkey .
An Olympic long jumper leaves the ground at an angle of 23 degrees and travels through the air for a horizontal distance of 8.7 meters before landing. What is the takeoff speed of the jumper?

Let the initial velocity = Vo
The horizontal comonent, Vx = Vo(cos23)
The horizontal distance, x = Vo(cos23)t = 8.7m
t = 8.7m / Vo(cos23)
The vertical component of initial velocity is Vyo:
Vyo = Vo(sin23)
Let the final vertical velocity be Vyf. Then,
Vyf = 0 (a the highest position)
0 = Vo(cos23)  9.8m/s^2*t, or:
t = Vo(cos23) / 9.8m/s^2
You have two expressions for time, t.
Since the two are equal, you can solve for Vo 
Well this must be a pretty common question because I had it too. The problem here is the Voy is Vo(SIN(23) not cos)/10.0 (or 9.8).
Also because the Vfy is 0 in the middle of the jump used only use half the X for the horizontal component. This is how I got the 11 m/s initial take off speed.
I don't know for sure, but that's how I'm solving these type of questions.
Respond to this Question
Similar Questions

physics
An athlete executing a long jumper leaves the ground at a 27.0 degree angle and travels 7.89 m. What was the takeoff speed? 
physics
An athlete executing a long jumper leaves the ground at a 27.0 degree angle and travels 7.89 m. What was the takeoff speed? 
math/ physics
An athlete executing a long jumper leaves the ground at a 27.0 degree angle and travels 7.89 m. What was the takeoff speed? 
Physics
A long jumper leaves the ground at an angle of 20 degrees and travels a horizontal distanceof 7.0m before landing. What is the takeoff speed of the jumper? 
Physics
An Olympic long jumper is capable of jumping 8.3 m. Assume that his horizontal speed is 9.5 m/s as he leaves the ground. He was in the air for .87 seconds. How high does he go assuming that he lands upright, the same way he was when … 
physics
1)A fire hose held near the ground shoots water at a speed of6.5 mps At what angle should the nozzle point in order that the water land 2.5 meters away? 
physics
A baseball is hit with a speed of 27 meters per second at an angle of 45 degrees. It lands on the flat roof of a 13 meter tall building. If the ball was hit when it was 1 meter above the ground, what horizontal distance does it travel … 
physics
I do not understand the answer that was given to me on a post dated Nov. 23. Please help explain my questions that appear at the end of this post. Bart  Posted by Bart on Wednesday, November 23, 2011 at 6:52am. A … 
Physics
A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the longjumper. 
physics
An Olympic long jumper leaves the ground at an angle of 18.7 ° and travels through the air for a horizontal distance of 7.04 m before landing. What is the takeoff speed of the jumper?