Problem 5-108 Force and Kinematics - Part 8

Tiny Tompfind, a man of mass \(72\; kg\), jumps (from rest) from a table \(92 \;cm\) to the floor below. As he lands, he bends his knees so that he decelerates over a distance of \(35 \;cm\).

(a) What is Tiny's speed just as he hits the floor?
(b) As he decelerates, what is the magnitude of the force exerted on him by the floor?

Accumulated Solution

FBD of Tiny jumping.

(C)   \(v_{y{^2}} = v_{0y{^2}} + 2a_yy= 4.2\; m/s\; \text{ (answer to part (a))}\\ a_y = -25.8 \;m/s^2\)

FBD indicating forces.

(A)   \(\sum F_y = ma_y \\ \sum F_y = mg - F\)

\(\sum F_y  = mg - F = ma_y \\ F = m(g - a_y) = (72 \;kg)[9.8\; m/s^2 - (-25.8\; m/s^2)] = 2.6 \times 10^3\; N   \; \text{(answer to part (b))}\)


You have completed this problem.