OSHA, the Occupational Safety and Health Administration, has established shandards for workplace exposure to noise. According to OSHA's Hearing Conservation Standard, the permissible noise exposure per day is 93.0 dB for 4 hours or 103 dB for 1 hour. Assuming the eardrum is 9.5 mm in diameter, find the energy absorbed by the eardrum, when subjected to each of these conditions.
(a) 93.0 dB for 4 hours
(b) 103 dB for 1 hour
(c) Is OSHA's safety standard simply a measure of the amount of
energy absorbed by the eardrum?
Y or N
Explain.
In: Physics
The position of a particle is given by x = 1/3t3 - 2t2 and y = 1/2t2 - 2t. Positions are in meters and time is in seconds. Complete the following table. θ is the angle between v and a, dv/dt is the rate at which the speed is changing, and R is the radius of the trajectory's tangent circle.
| t (s) | v (m/s) | a (m/s/s) | θ (deg) | dv/dt (m/s/s) | R(m) |
| 2.00 | i + j | i + j | |||
| 3.00 | i +j | i + j | |||
| 4.00 | i + j | i + j |
In: Physics
1)During a thunderstorm, a lightning "bolt" carries current
between a cloud and the ground below. If a particular bolt carries
a total charge of 39 C in 1.2 ms, what is the magnitude of the
current?
A
How many electrons are involved in this process?
electrons
In: Physics
A cart of mass m1 = 11 kg slides down a frictionless ramp and is made to collide with a second cart of mass m2 = 24 kg which then heads into a vertical loop of radius 0.25 m (a) Determine the height h at which cart #1 would need to start from to make sure that cart #2 completes the loop without leaving the track. Assume an elastic collision. (b) Find the height needed if instead the more massive cart is allowed to slide down the ramp into the smaller cart.
In: Physics
A Parasail rider wants to reach the maximum height allowed by the Federal Aviation administration... A Parasail rider wants to reach the maximum height allowed by the Federal Aviation administration if the rider’s boat is to tow the parachute at 30 miles per hour. How should the tow to reach the maximum flying height? A. Draw and label a diagram to represent this situation. B. Explain two different methods to solving this problems Method 1: Method 2: C. Find the length of the tow line using both methods from part (b) Write a “ rule of thumb” that does not require trigonometry for calculating the maximum height of a parasail rider given the length of the tow line?
In: Physics
A spring-loaded gun fires a 0.080-kg puck along a tabletop. The
puck slides up a curved ramp and flies straight up into the
air.
(a) If the spring is displaced 24.0 cm from equilibrium and the spring constant is 875 N/m, how high does the puck rise, neglecting friction?
x = m
(b) If instead it only rises to a height of 5.00 m because of
friction, what is the change in mechanical energy?
Wnc =
In: Physics
A positive charge 1.1X10-11 C is located 10-2 m away from a negative charge of the same magnitude. Point P is exactly half way between them --what is the E field at point P?
In: Physics
In a rectangular coordinate system, a positive point charge q = 8.00 nC is placed at the point x = +0.150 m, y = 0, and an identical point charge is placed at x = -0.150 m, y = 0. Find the electric field at the following points.
a. Find the x and y components of the electric field at x = 0.150 m, y = -0.400 m. (Units N/C)
b. Find the magnitude of the electric field at x = 0.150 m, y = -0.400 m. (Units N/C)
c. Find the direction of the electric field at x = 0.150 m, y = -0.400 m. (Units degrees)
In: Physics
A) The resistivity of blood is related to its hematocrit, the volume fraction of red blood cells in the blood. A commonly used equation relating the hematocrit h to the blood resistivity ρ (in Ω⋅m) is ρ=1.32/(1−h)−0.79. In one experiment, blood filled a graduated cylinder with an inner diameter of 0.90 cm. The resistance of the blood between the 1.0 cm and 2.0 cm marks of the cylinder was measured to be 246 Ω. What was the hematocrit for this blood?
B) When the starter motor on a car is engaged, there is a 310 AA current in the wires between the battery and the motor. Suppose the wires are made of copper and have a total length of 1.2 mm . What minimum diameter can the wires have if the voltage drop along the wires is to be less than 0.60 VV ? Express your answer in millimeters.
C) Variations in the resistivity of blood can give valuable clues to changes in the blood's viscosity and other properties. The resistivity is measured by applying a small potential difference and measuring the current. Suppose a medical device attaches electrodes into a 1.5-mmmm-diameter vein at two points 5.0 cmcm apart. What is the blood resistivity if a 8.8 VV potential difference causes a 220 μAμA current through the blood in the vein? Express your answer in ohm meters.
In: Physics
A flint glass plate (n = 1.66) rests on the bottom of an aquarium tank. The plate is 10.00 cm thick (vertical dimension) and covered with water (n = 1.33) to a depth of 12.3 cm. Calculate the apparent thickness of the plate as viewed from above the water. (Assume nearly normal incidence of light rays.)
In: Physics
A sample of ideal gas is placed inside a balloon at room temperature. The balloon is then put inside a freezer, where it deflates without losing any of the gas inside it. The system is the gas inside the balloon.
I - Represent this process with a PV diagram.
II - Was the change in internal energy of the system, positive, negative, or zero? How do you know?
III - Was the work done by the atmosphere on the system positive, negative, or zero? How do you know?
IV - Was the energy supplied to the system by heating positive, negative, or zero? How do you know?
V - Represent this process with a work-energy bar chart.
In: Physics
A cylinder, which is in a horizontal position, contains an unknown noble gas at 48400 Pa and is sealed with a massless piston. The piston is slowly, isobarically moved inward 18.9 cm, which removes 18600 J of heat from the gas. If the piston has a radius of 27.2 cm, calculate the change in the internal energy of the system Δ U
In: Physics
Chose the right answer
a) If we decrease the size of a quantum dot that contains an electron, what happens to the energy levels?
1-Decrease
2-remain the same
3-increase
b) If two quantum states are degenerate, which is true?
1- They have identical momenta.
2- They have identical wave functions
3- They have identical energies
C) Which is true about the electron in a hydrogen atom?
1-Its total energy and potential energy are negative
2-Its kinetic energy and potential energy are negative
3-Its total energy and kinetic energy are negative.
d) Which quantum number determines the energy of the hydrogen atom?
1- orbital quantum number
2- principal quantum number
3- orbital magnetic quantum number
In: Physics
The most basic explanation for the Heisenberg Uncertainty Principle is that the momentum and position of a quantum particle is not very distinct when an attempt is made to measure them together. But what is it that causes the uncertainty? Because if there is no change in the momentum, then it would be the same as measuring the two separately. So what causes this change in the instantaneous perceived momentum. A change in mass? Velocity? Or net composition of the particle?
In: Physics
A 150-V battery is connected across two parallel metal plates of area 28.5 cm2 and a separation of 8.20 mm. A beam of alpha particles (charge +2e, mass 6.64E-27 kg) is accelerated from rest through a potential difference of 1.75 kV and enters the region between the plates perpendicular to the electric field.
What magnitude and direction of magnetic field are needed so that the alpha particles emerge undeflected from between the plates?
In: Physics