# Jason takes off across level water on his jet-powered skis. The combined mass of Jason and skis is 75 kg (the?

0

Jason takes off across level water on his jet-powered skis. The combined mass of Jason and skis is 75 kg (the mass of the fuel is negligible). The skis have a thrust of 200 N and a coefficient of kinetic friction on water of 0.1. Unfortunately, the skis run out of fuel after only 11 s. How far has Jason traveled when he finally coasts to a stop?

A. 24 m/s

B. 90 m/s

Also Check This  How to solve 2(12-8x) = x-11x … ?

C.150 m/s

D.240 m/s

• newton’s second law tells us

sum of forces = ma

while he has fuel, this becomes

thurst – friction = ma

thrust = 200N, friction = u mg = 0.1*75kg*938m/s/s

thus,

200N – 73.5N = 75 a

a=1.69m/s/s

in the first 11 seconds, Jason reaches a velocity of

v= a t = 1.69m/s/s x 11 s = 18.6m/s

and travels a distance dist = 1/2 a t^2 = 1/2(1.69m/s/s)(11s)^2 = 102.2m

once he runs out of fuel, the only force acting on him is friction, so his acceleration then is

F = ma = u mg or a = u g = 0.98m/s/s

and we find the distance he travels while coasting from

vf=final velocity =0

v0=initial velocity = 18.6m/s

a=accel = -0.98m/s/s

d=distance traveled

0=18.6^2-2*0.98*d => d=176.5m

add the two distances to find his total distance traveled 