[onk]

onk on September 14, 2005 at 7:42 am #11261

An olympic long jumper leaves the ground at an angle of 23 and traveled a distance of 8.7m before landing. Find the speed at takeoff.

Ok, so i've tried to plug in datas in formulas but i keep getting the wrong answer. The answer is suppose to be 11 m/s. CAn someone guide me in a step by step method to getting the answer? I know i must first find the initial vertical and horizontal speed but i cant arrive at the correct one!

(by the way i'm new in physics)

[Mike Young]

Mike Young on September 16, 2005 at 1:03 am #48525

Which of the equations of constant motion are you using?

You should be using this one:

v²_f = v²_i + 2ad

Where:
*v_f = the final velocity (zero in this case)
*v_i = the horizontal component of the initial velocity
*a = acceleration due to gravity
*d = distance traveled (8.7m)

Be sure you are determining the resultant velocity from the horizontal component (the above equation will help you solve for only the horizontal component) and you are squaring the values that need to be squared.

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