33-131
Matter & Interactions I
Fall 2012
Assignment 1 Solutions
1.C38. A subatomic particle is located at the point (3 1010 , 3 1010 , 8 1010 ) m. (a)
What is the vector r that goes from the origin to the particle? (b) What is the
magnitude of the vector,
33-131
Matter & Interactions I
Fall 2012
Assignment 7 Solutions
5.C10. A force F acts on extended object of mass M as it moves through a distance D. The
object starts from at rest. After the object has moved through the distance D, it has
a center-of-mass
33-131
Matter & Interactions I
Fall 2012
Assignment 6 Solutions
4.S42. The escape speed of an asteroid whose radius is 10 km is 10 m/s. (a) What is the mass
of the asteroid? (b) A 20 kg object is thrown from the surface of the asteroid with a
speed of 20
33-131
Matter & Interactions I
Fall 2012
Assignment 4 Solutions
3.C22. A an object of mass m is held up by two rods of dierent length as shown in Figure ?.
(a) In terms of m, g , and , what are the tensions in the two rods? (b) You are
told that m = 650 g
33-131
Matter & Interactions I
Fall 2012
Assignment 2 Solutions
1.C42. An object is initially moving in the x direction with momentum p = 8 kg m/sx. A
constant force, F = 7 N x +5 N y , acts on the object for a time interval of t = 0.13 s.
(a) What is the
33-131
Matter & Interactions I
Fall 2012
Assignment 8 Solutions
a
a
a-b
b
Figure 1: The spherical shell for problem 7.C3.
7.C3. The moment of inertia of a uniform sphere of mass m and radius r about its center is
22
mr .
5
What is the moment of inertia of
33-131
Matter & Interactions I
Fall 2012
Assignment 9 Solutions
ra
rb
M,I
rb
ra
F
M,I
Figure 1: A disk being pulled across a rough surface by a string wound around its hub for problem
7.C23.
7.C23. An object built of three disks is shown in Figure 1. The
33-131
Matter & Interactions I
Fall 2012
2.C11. A bug is hovering over a highway when it is struck by the windshield of a moving car.
(a) Considering the Earth, the bug and the car as relevant objects, in which systems
is the change of momentum zero? (b)
Work each of the following problems on your white board. When you have completed a
problem, please have an instructor come and sign o that you have done it correctly.
m1 m2
r2
G = 6.67 1011 N m2 /kg 2
1 q1 q 2
| Fele | =
4 0 r2
1
= 9 109 N m2 /C 2
4 0
rat
33-131
Matter & Interactions I
Fall 2012
Assignment 11 Solutions
9.C13. Helium gas is produced from the radioactive decay of Uranium and Thorium inside
the Earth. The gas is a by product of natural gas and oil extraction from deep wells,
where some of the
33-131
Matter & Interactions I
Fall 2012
Assignment 10 Solutions
8.S44. A scattering experiment is to be set up to bounce projectiles of mass m o targets of
mass 10m. The targets are initially at rest, and the projectiles all have speed vi and
you may ass