Problem 12.62 The magnitude of the tidal force exerted on an object of mass m an
ID: 1466621 • Letter: P
Question
Problem 12.62
The magnitude of the tidal force exerted on an object of mass m and length a is approximately 4GmMa/r3.
In this expression, M is the mass of the body causing the tidal force and r is the distance from the center of m to the center of M. Suppose you are 1.0×106 mi away from a black hole whose mass is a 1.2×106 times that of the Sun. Estimate your mass to be 71 kg and your length to be 1.7 m .
Part A
Estimate the tidal force exerted on your body by the black hole.
Express your answer using two significant figures.
THE ANSWER IS F=4.59N****
Part B
At what distance will the tidal force be approximately 14 times greater than your weight?
Express your answer using two significant figures.
THE ANSWER IS NOT r2=1.25*10^8m****
Second time posting. Please help !!
Explanation / Answer
r = 10^6 miles = 10^6*1609.44 m
a = 1.9 m
M = 1.2*10^6*Ms = 1.2*10^6*2*10^30 kg
m = 71 kg
F = 4GMma/r^3
F = (4*6.67*10^-11*1.2*10^6*2*10^30*71*1.7)/((10^6*1609.344)^3
F = 18.54 N <<----------answer
++++++++++
part(B)
if F = 14*W = 14*71*9.8
14*71*9.8 = (4*6.67*10^-11*1.2*10^6*2*10^30*71*1.7)/(r2)^3
r2 = 1.99*10^8 N <<----------answer