The determined Wile E. Coyote is out once more to try to capture the elusive roa
ID: 2167451 • Letter: T
Question
The determined Wile E. Coyote is out once more to try to capture the elusive roadrunner. The coyote wears a new pair of power roller skates, which provide a constant horizontal acceleration of 15 m/s2, as shown in the figure below. The coyote starts off at rest 70 m from the edge of a cliff at the instant the roadrunner zips by in the direction of the cliff.
(a) If the roadrunner moves with constant speed, find the minimum speed the roadrunner must have to reach the cliff before the coyote.
m/s
(b) If the cliff is 100 m above the base of a canyon, find where the coyote lands in the canyon. (Assume that his skates are still in operation when he is in "flight" and that his horizontal component of acceleration remains constant at 15 m/s2.)
m from the base
Explanation / Answer
a) s=ut+0.5at^2 70=0+0.5*15*t^2 t=3.055 s (time for WEC to reach edge) Roadrunner speed = dist / time = 70 / 3.055 = 22.9 m/s b) Vertical motion only: s=ut+0.5at^2 -100=0-0.5*9.81*t^2 t=4.52 s Horz motion only: s=ut+0.5at^2 s=0+0.5*15*(4.52+3.055)^2= 429.8 m from original start point Thus 429.8 - 70 = 359.8 m from the edge of the cliff