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A grinding wheel, initially at rest, is rotated for 8 seconds with a constant angular acceleration of 5 rad/s^2. The wheel is then brought to rest, with a uniform negative angular acceleration, in 10 revolutions. (a) Determine the angular acceleration needed. (b) How lng did it take to bring it to rest? *
Standing waves are established in a string. The frequency of the wave is 512 Hz and the
distance between two successive nodes is 8 cm. Calculate the velocity of the wave in the
string.
A standing wave is set up in a string 120 cm long. The string vibrates in four segments under
a frequency of 120 Hz. Calculate the wavelength and the fundamental frequency of the string
Water flows through a venturi meter. At the constricted section where the area is 24 cm2
, the
pressure is 10.2 N/cm2
, and at the section where the area is 64 cm2
, the pressure is 18.0 N/cm2
.
Determine the velocities of water in the larger and smaller pipes and the rate of flow.
It has been estimated that a man’s heart is about 33 cm below his brain. Considering the density
of human blood to be 1.1 x 103 kg/m3
, what pressure must the heart produce to supply blood to
the brain?
A round and smooth table revolves around an axis that passes through its center at a constant angular velocity w. The two bodies are moving together on the table. Body A whose mass m is attached to the table hinge by means of a spring. The force constant of the spring is k and the length of the spring in the relaxed state is L. Body A is connected to body B whose mass is 2m by A wire.
At the time of rotation, the distance of body A from the center is R and of body, B is 2R Beta using w, L, m, k the
1. The radius of rotation R of body A.
2. What is the stretching of the wire connecting the bodies.
3.Determine, without calculating which of the two bodies exerts a greater equivalent force?
4. Does the expression you found in section 1 have a physical meaning at any angular velocity?
5. Calculate the mass of each of the bodies given: w = 3rad / sec; k = 72N / m; L = 0.5m; R = 1m
6. What is the work of the wire that connects the two bodies while the bodies complete one round. Necrosis.
how can you conserve energy in you household?
DETERMINE RESISTANCEFROM CURRENT-VOLTAGE
Suppose you apply several different voltages across a circuit and measure the current that runs through the circuit. NOTE: the current is given in milliamperes. Example, at 2 voltage, the current is 0.002A or 2mA. What is the resistance of the circuit?
A heavy disk of radius R is placed on an axle through its axis of symmetry perpendicular
to the disk. The disk is given angular velocity! about the axis and then is released. Because of
friction in the axle, the disk slows down and stops rotating after time T. How long will it take for
the same disk but of radius 2R to stop if it is given the same initial angular velocity? Assume the
disks are of uniform density, same thickness, and that the friction in the axle is the same in both
cases.
When the frictionless system where a 6kg block is pushing a 3kg block is accelerated by an applied force of magnitude F, the tension in the string between the blocks is
(A) F (B) (2/3) F (C) ½ F (D) (1/3) F
