Jason takes off across level water on his jet-powered skis.The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible).Water exerts a force of 200 N on the skis.The coefficient of kinetic friction between the skis and water is 0.10.Unfortunately,the skis run out of fuel after only 41 s.How far from his starting point has Jason traveled when he finally coasts to a stop?
A)3900 m
B)2900 m
C)2000 m
D)1400 m

Question

Quizplus · Accepted Answer

Explanation:The force of kinetic friction is:$$f_k=\mu_kn=\mu_kmg=0.10(75	ext{ kg})(9.8	ext{ m/s}^2)=73.5	ext{ N}$$The net force on the skis is:$$F_{net}=F_w-f_k=200	ext{ N}-73.5	ext{ N}=126.5	ext{ N}$$The acceleration of the skis is:$$a=\frac{F_{net}}{m}=\frac{126.5	ext{ N}}{75	ext{ kg}}=1.69	ext{ m/s}^2$$The distance traveled by the skis is:$$d=\frac{1}{2}at^2=\frac{1}{2}(1.69	ext{ m/s}^2)(41	ext{ s})^2=\boxed{2900	ext{ m}}$$

Jason Takes Off Across Level Water on His Jet-Powered Skis