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Jason takes off across level water on his jet-powered skis
The combined mass of Jason and his skis is 75kg (the mass of the fuel is negligible)
The skis produce a forward thrust of 200N and have a coefficient of kinetic friction with water of 0.10
Unfortunately, the skis run out of fuel after only 41s
How far from his starting point has Jason traveled when he finally coasts to a stop?

Respuesta :

metchelle
Thrust - Friction = mass * acceleration

Friction = coefficient * mass * gravity
Friction = 0.10 * 75 * 9.8 = 73.5 N

Substituting:
200N - 73.5 = 75a
a = 1.69 m/s^2

Obtaining final velocity at the end of 41 seconds:
Vf = at
Vf = 1.69 (41)
Vf = 69.15 m/s

Using the formula for displacement for linear motion problems:

s = Vo*t + (1/2)a*t^2
s = 0 + (1/2)(1.69)(41^2)
s = 1420.445 meters

After he runs out of fuel, we use the following formula to find the distance that he coasts:

F = ma = coefficient*m*g
a = 0.10(9.8)
a = -0.98

Vf^2 = Vo^2 + 2as
0 = 69.15^2 + 2(-0.98)s
s = 2439. 65

Adding the 2 displacements together to obtain the total distance:

Total distance = 2439.65 + 1420.45 meters
Total distance = 3860.1 meters

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