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shawonna23
Sep5-04, 10:31 PM
The land speed record of 13.9 m/s (31 mi/h) for birds is held by the Australian emu. An emu running due south in a straight line at this speed slows down to a speed of 10.5 m/s in 2.7 s.

What is the direction of the bird's acceleration?

Assuming that the acceleration remains the same, what is the bird's velocity after an additional 3.9 s has elapsed?

JasonRox
Sep7-04, 10:31 PM
Hint:

a=\frac{v_f-v_i}{t}

Beer-monster
Sep8-04, 02:55 AM
Hint: If it slows down it is decelerating i.e negative acceleration

HallsofIvy
Sep8-04, 07:35 AM
Also, "speeding up" means speed is increasing: acceleration is "positive"- in same direction as velocity.

"Slowing down" means speed is decreasing: acceleration is "negative"- in opposite direction to velocity.