Phy 61: Introductory Mechanics
February 15, 2008
Directions: Print your name and recitation section number at the top of this page. Write complete answers to all questions and problems in the space provided. The tota
1e)[6 points] A ball hits a well at 30" to the sis-axis with speed 20m/s as shown. It bounces
back with speed ZOm/s at 30" to the :c axis. If the collision lasted for 0.13, nd the direction
and magnitude of the average force acting on the bell in that per
1a) [5 points] Two masses of .1Kg are coniiected by a, spring that is compressed and has
potential energy of 16.]. The entire set up is at rest when the spring is released. What are
speeds of the two masses when they separate from the spri
PHY 141 Summer 2013 Exam 2
Name: -. Recitation Sec.:
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Pmblem 1 (20 points):
A mass of 1K9 is looping a vertical loop0f radius 5m. The iioririal force on the particle
at the top of the circie is lON.
i)Find the speed of the palticle at the top of 1119, circle?(5 poinis)
lrlma 9 H LT
10) [6 pts.] The graph of a force acting on a mass of 1K9 with respect to distance is provided.
The force is measured in Newtons and the distance in meters. If a particie starts at rest
from :1: x 1m, nd its speed when it reaches a: = 4m.
1d) [6 pts.] A
Problem 2 (20 points):
A particle of mass m = 1K9 is moving nder a potential given by U (3:) = (3:2 - 433).]
where :1: is measured in meters from a xed origin.
i)Find an expression for. the force as a, function of distance and nd the point(s) of
iii) Find the normal force on the particke at the bottom of the circle. (4 points)
M W I
N T N -m 2: m1-
iv)lf a spring of stiffness factor IOON/m is attached at the bottom! of the circle as shown,
1g) [6 13135.] A pipe has cross sectional area of 1m2 at the inlet end and area. of 0.51312 at the
outlet end. The pressure at the inlet end is ve times the atmospheric pressure and the
inflow speed is 10m/9. What are the pressure and ow speed at the outl