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Homework Statement
A rubber ball (mass 0.26 kg) is dropped from a height of 1.7 m onto the floor. Just after bouncing from the floor, the ball has a speed of 3.6 m/s.
(a) What is the magnitude and direction of the impulse imparted by the floor to the ball? Magnitude ? kg · m/s
(b) If the average force of the floor on the ball is 17 N, how long is the ball in contact with the floor?
Homework Equations
dp=Fdt=m(vf-vi)
The Attempt at a Solution
a)the unknown is the initial speed of the dropping ball under free fall:
vi= sqrt (2 x 9.8 x 1.7) = 5.8
delta p= 0.26 (3.6--5.8)=2.4
b) dt=dp/Fave=0.14 s
Please let me know what is wrong here, my electronic assignment system is telling me the numbers are wrong. Thank you!