- #1
sona1177
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Homework Statement
A crate pushed along the floor with velocity Vi slides a distance d after the pushing force is removed.
a)If the mass of the crate is doubled but the initial velocity is not changed, what distance does the crate slide before stopping? Explain.
b) If the initial velocity of the crate is doubled to 2vi but the mass is not changd, what distance does the crate slide before stopping? Explain.
*I know this question was posted before but in this case, the Professor told me I can include friction, so this changes the question completely.
Homework Equations
F=ma
F=max (object is moving horizontally)
The Attempt at a Solution
Fnetx=nx + wx + Kfx where Kfx stands for the kinetic friction, n is the normal force, and w is weight pulling down on the object.
Fnet= -Kf (kinetic friction opposes motion, so the value is negative
nx=0
wx=0
-Kf/m=ax
I don't think I include the pushing force because it is removed after the initial velocity.
Kinetics Equation:
V2=Vi2 + 2a(Xf-Xi)
0=Vi2 + 2a(Xf-Xi)
-Vi2=2(Kf/m)d (where d stands for Xf- Xi)
Doing algebra: d=-mVi2/ (2*Kf) (in this equation only the Vi is squared, in the denominator, the answer is (2 times kf). I hope that is clear.
b) -m * 2 * Vi2/2 *Kf (in this equation its 2 times the initial velocity squared divided by 2 times Kf) therefore the 2's cancel out and I get the same answer as I did for part a: -m* Vi2/Kf=d
I hope this makes sense. Is my work and answer correct?
Thank you kindly for taking the time to help me! :)