1] A 0.150 kg object tied to a string is
whirled
in a horizontal circle at a constant angular speed

of 3.50 revolutions/sec.
The tension in the string is 75.0 N. What is the length of the string?

ANSWER: 1.03 m

2] A wheel of diameter 0.80 m is initially
at
rest. It is then rotated with a constant angular

acceleration of 5.0 rad/s^{2}
for exactly 10 revolutions of the wheel. Determine both the angular

speed of the wheel and the
tangential speed for a point on the edge of the wheel at the end

of the 10 revolutions.

ANSWER: 25 rad/s , 10 m/s

1] A 150 gm object tied to a string is
whirled
in a horizontal circle such that the tension in the

string is 75.0 N when the
angular speed is 3.50 revolutions/sec. How many meters, **s**, does

the object travel in 5.00
seconds? [ NOTE
**s** is the circumferential distance traveled around

the circle.]

3] A uniform beam 3.00 meters long has a
weight
of 245 N. It is supported on its left end by a cable.

A 500 N weight is located
on the beam a distance of 1.00 meter from the left end. You supply a

force to the right end of
the beam so that the beam is in equilibrium in the horizontal position
(see

sketch). What are the
tension
in the cable, T, and the upward force, F, you must apply to the beam?

** {HINT : Apply the
equilibrium
condition for two different axis’ of rotation !!}**

3] A solid wood sphere floats in alcohol (r
= 0.806 x 10^{3} kg/m^{3}) such that exactly one half
of
the

sphere is submerged in the
fluid.

A} Find the density of the wood.

ANSWER: 403 kg/m^{3}

B}
Give the name and __define__ the principle involved in the solution
of this problem.

ANSWER: Archimedes principle

4] A concrete canoe must be constructed
such that
most of its volume is air to insure that it will float in

water. Assume such a canoe can be
approximated as a
uniform solid cube with sides 2.0 meters in length.

When placed in water, the cube floats upright
with its bottom 1.5 meters below the water surface.

A)
Find the
average density for the concrete
canoe.
ANS: 0.75 gm/cm^3

B)
Find the
absolute pressure at the bottom
of the canoe.
ANS: 1.16 x 10^5 Pa

3] A
uniform beam 4.00 meters long has a
weight of 350 N. It
is supported at a point 1.00 meter from
the right

end by a fulcrum. A 500 N
weight is located on the beam a distance of 1.00 meter from the left
end. You supply a force

directed at the
right end of the beam so that the beam is in equilibrium in the
horizontal
position (see sketch).

Determine BOTH the
force exerted by you on the right end AND the force exerted on the beam
by the
fulcrum.

ANS: F = 1560
N Fulcrum = 2200 N

M ultiple
Choice

- Consider a point on a bicycle wheel as the wheel turns
about a fixed axis, neither speeding up nor slowing down. Compare the
linear and angular accelerations of the point.
- Both are zero.
- Only the angular acceleration is zero.
- Only the linear acceleration is zero.
- Neither is zero.

- If the net torque applied to an object is zero,
then that object will experience:
- a constant angular velocity
- an angular acceleration
- a centripetal acceleration
- no angular motion at all

a. centrifugal force

b. centripetal force

c. outward pushing force

d. no force is required for circular motion

4. Water pressure is the greatest against the

a. top of a submerged object

b. bottom of a submerged object

c. sides of a submerged object

d. is the same for all surfaces

e. none of the above

5. The buoyant force on an object will have its smallest value when the object is

a. only partly submerged

b. completely submerged but near the surface

c. completely submerged but near the bottom

d. the force is the same whether it is partly or completely submerged

6. You sit on one end of a seesaw and your classmate sits on the other. You are a distance A from

the fulcrum and your classmate is a distance B from the fulcrum. The lever arm distance for the

torque you exert on the fulcrum pivot point is

a) A + B

b) A - B

c) A

d) B

e) (A+B)/2

Answers::

1) a

2) d

3) b

4) b

5) a

6) c