Question

A sled slides along a horizontal surface for which the coefficient of kinetic friction is 0.25. Its velocity at point A is 8.0 m/s and at point B is 5.0 m/s. Use the impulse-momentum theorem to find how long the sled takes to travel from A to B.

Answer 1

sled takes 1.22 seconds to travel from A to B.

Explanation:

impulse = change in momentum

$Force \times time = mass 2 \times velocity 2(vf) - mass 1 \times velocity 1(vo)$

$F \times t = m(vf - vo)$

$F \times u \times t = m(vf - vo)$

$mg \times u \times t = m(vf - vo)$    ( $F = mg$)

$g \times u \times t = vf - vo$

$t = \frac{vf -vo}{g \times u}$

$t = \frac{(8 - 5)}{(9.8 \times 0.25)}$

$t = 1.22 s$

t = 1.22 seconds.