Need help bulk modulus problem

by hannsparks
Tags: bulk, modulus
hannsparks is offline
Feb15-06, 10:34 AM
P: 32
A solid ball of a special plastic material is to be used as a replacement joint for a patientís hip. The mass per unit volume density of the ball is 900 kg/m3 and its radius is 1.5 cm. The ball is subjected to a test in which it is subjected to an increase in external pressure of 2 X 10 8 N/m2. The Bulk modulus of the ball is 2 X 10 9 N/m2.
Assuming that the ball is compressed uniformly during this test, find the mass
per unit volume density of the ball in its compressed state. The volume
formula for a sphere of radius r is 4/3 pi r 3 .

what Ive done so far:
Volumem initial =1.414e-5

change p= -B changeV/initial V

change V=-1.414e-6

mass of ball= 900 x 1.414e-5=.012735

Im not really sure hwat to do next I tried to solve for density of the ball using the mass .012735 and the volume (change and then intitial) but both answers were wrong I know the answer is supposed to be 1000kg/m3 according to the book but im not getting that

please help
Phys.Org News Partner Science news on
SensaBubble: It's a bubble, but not as we know it (w/ video)
The hemihelix: Scientists discover a new shape using rubber bands (w/ video)
Microbes provide insights into evolution of human language

Register to reply

Related Discussions
Question Regarding Bulk Modulus Introductory Physics Homework 1
Bulk Modulus of an Ideal Gas Advanced Physics Homework 2
Bulk Modulus Materials & Chemical Engineering 1
Bulk modulus Classical Physics 3
Bulk modulus Atomic, Solid State, Comp. Physics 1