- #1
Nightrider55
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Homework Statement
Fred (mass 60.0kg) is running with the football at a speed of 6.0m/s when he is met head-on by Brutus (mass 120kg), who is moving at 4.0m/s. Brutus grabs Fred in a tight grip, and they fall to the ground. How far do they slide?
Part A
The coefficient of kinetic friction between football uniforms and Astroturf is 0.3.
Give answer in cm
Homework Equations
MfVf + MbVb=(Mf+Mb)Vs
Kinematics
Ax=-mew x g
The Attempt at a Solution
I did the problem and doubled check my work and even had a friend check it and we couldn't find a mistake but I still get it wrong
To find the velocity after the collision I used the conservation of momentum equation above and calculated the "after impact) velocity to be -2/3 m/s. I then proceeded to find the acceleration and used Ax=-mew x g and got -2.94 m/s^2. From there I solved for time by plugging the velocity and acceleration into Vfx=Vix+Ax(delta T). I got the time for
the slide to be .22 seconds. I then plugged everything into the distance kinematics equation Xf=...and I got .075 m which I then converted to 7.55 cm, but it still says its wrong. Do you see any mistakes I made?