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a) A crate of mass 50.1 kg rests on a level surface, with a coefficient of kinet

ID: 1554420 • Letter: A

Question

a) A crate of mass 50.1 kg rests on a level surface, with a coefficient of kinetic friction 0.73 . You push on the crate with an applied force of 753 N. What is the magnitude of the crate's acceleration as it slides? ________m/s2

d)Different situation now. Youre out in space, on a rotating wheel-shaped space station of radius 1097 m. You feel planted firmly on the "floor", due to artificial gravity. The gravity you experience is earth- normal, that is, g=9.8 m/s2. How fast is the space station rotating in order to produce this much artificial gravity? ___________revolutions per minute (rpm)

e)What would the radius of the space station have to be, rotating at the rate you calculated in part (d), to produce artifical gravity of 30 m/s2? ____________m

Explanation / Answer

a)

acceleration a = Fnet /m

Fnet = F - fk = F - uk*m*g

a = (753 - (0.73*50.1*9.81))/50.1


a = 7.87 m/s^2   <<<--------answer

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(b)


acceleration a = Fnet /m

Fnet = m*g*sintheta - fk = m*g*sintheta - uk*m*g*costheta

a = g*(sintheta - uk*costheta)


7.87 = 9.8*(sintheta - (0.73*costheta))


sintheta = x

costheta = sqrt(1-x^2)


7.87 = 9.8*(x - (0.73*sqrt(1-x^2)))

sintheta = 0.97


theta = 76 degrees <<<--------answer


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(c)


if uk = 0

a = g*sintheta

7.87 = 9.8*sintheta

theta = 53.4 degrees   <<<--------answer


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(d)

acceleration a = r*w^2

9.8 = 1097*w^2

w = 0.0945 rad/s

w = 0.0945*60/(2pi)

w = 0.902 rpm   <<<--------answer

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(e)

for a = 30 m/s^2

30 = r*0.0945^2

r = 3360 m <<<--------answer