Question

A luge run is straight for the first 10 m. If the velocity of the luger when he passes the start line is +25 m/s and his acceleration is constant at +9.5 m/s2, about how fast is he going when he hits the first turn? A. +14 m/s B. +26 m/s C. +29 m/s D. +225 m/s

Answer 1

Recall that

`{v_f}^2-{v_i}^2=2a\Delta x`

where
`v_i` is the luger's initial velocity,
`v_f` his final velocity,
`a` his acceleration, and
`\Delta x` the distance he traverses. Then

`{v_f}^2-\left(25\,(\mathrm m)/(\mathrm s)\right)^2=2\left(9.5\,(\mathrm m)/(\mathrm s^2)\right)(10\,\mathrm m)`

`\implies v_f\approx29\,(\mathrm m)/(\mathrm s)`

so the closest answer is C.