Physicians perform needle biopsies to sample tissue from internal organs. A spri
ID: 1970355 • Letter: P
Question
Physicians perform needle biopsies to sample tissue from internal organs. A spring-loaded gun shoots a hollow needle into the tissue; extracting the needle brings out the tissue core. A particular device uses 8.6mg needles that take 93ms to stop in the tissue, which exerts a stopping force of 39mN.a) Find the impulse imparted by the tissue.
b) How far into the tissue does the needle penetrate?
I need help ASAP!! I don't even know where to begin with this -_-' thanks!
Explanation / Answer
a)Impluse = F*t = 42e-3*93e-3 = 3.91e-3Ns The impulse is the change in momentum. We know that Vf = 0 therefore the change in momentum is b)mVi = F*t = 8.4e-3Vi => Vi = 0.4654m/s => a = [Vf - Vi]/t = -Vi/89e-3 = -5.23m/s^2 Now use the equation Vf^2 = Vi^2 + 2*a*d => d = -Vi^2/2*a = 0.0207m = 20.7mm