(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Sam, whose mass is 75 kg, takes off across level snow on his jet-powered skis. The skis have a thrust of 200N and a coefficient of kinetic friction on snow of 0.10. Unfortunately, the skis run out of fuel after only 10 s.

a. What is Sam’s top speed?

b. How far has Sam traveled when he finally coasts to a stop?

2. Relevant equations

3. The attempt at a solution

Fnet = F(thrust) - Fk

where Fk = (coeff)mg

= (0.1)(75)(9.8)

= 73.5N

plug in to Fnet = F (thrust) - Fk

= 200 - 73.5

= 126.5N

To find acceleration:

Fnet = ma

126.5 = 75 a

a = 126.5/75

a = 1.69 m/s2

To find top speed:

Vf = Vi + a (deltaT)

Vf = 0 + 1.69(10)

= 16.9m/s

to find b... i have no idea.

i knwo that:

vi would be 16.9m/s

vf would be 0m/s

i dont know what the decelleration value is for when it is coasting

and i knwo that i use the equation: Vf^2 = Vi^2 + 2a (deltaX)

wehre delta (X) is change in position (displacment)

someone help!

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# Homework Help: Thrust and Kinetic Friction

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