A cell membrane has a resistance and a capacitance and thus a characteristic time constant

Part A

What is the time constant of a 7.7 nm -thick membrane surrounding a 4.0×10⁻² mm -diameter spherical cell? Assume the resistivity of the cell membrane as 3.6×106 Ω⋅m and the dielectric constant is approximately 9.0.

Express your answer to two significant figures and include the appropriate units.

I can roughly feel a force of 10 newton only by considering the weight of 1 kilogram object.

How to imagine the following measurements?

Maximum horsepower 16 hp @ 9,500 RPM

Maximum torque 12.76 N

An AC voltage with an amplitude of 130 V is applied to a series combination of a 224 μF capacitor, a 114 mH inductor, and a 15.7 Ω resistor.

Calculate the power dissipated by the circuit at a frequency of 50.0 Hz.

Calculate the power factor at this frequency.

Calculate the power dissipation at a frequency of 60.0 Hz.Calculate the power factor at this frequency.

Calculate the power factor at this frequency.

Application: Heating Food in a Microwave Oven. A frozen pizza is marketed to be heated in a microwave oven. As
an engineer you are asked to write heating instructions, specifically how long should it be heated to reach a proper
temperature. The average residential microwave oven is 50 cm wide, 40 cm deep, and 30 cm high. The oven has a low
and a high heating level. At low, it produces a time averaged power of 500 W, whereas at high, the power is 1000 W.
We will assume the pizza is placed flat on the bottom of the oven and any power coupled into the pizza enters from
above. The pizza is 25 cm in diameter, 1.5 cm thick, and is 75 % water by volume. The microwave oven heats the
water in the pizza. The frozen pizza is at –20 C and must be heated to 75 C. Heat capacity of water is 4.1885 J/
(gK) and the latent heat (of melting ice) is 334 J/g (heat capacity is the energy needed to raise the temperature of one
gram of substance (water in this case) by 1 degree Kelvin, and latent heat is the energy required to melt a gram of ice
at 0 C to water at 0 C). Assume that the heat transfer from the electromagnetic waves to the pizza is 80 % efficient
and calculate:
(a) The time it takes to heat the pizza on the low setting of the oven.
(b) The time it takes to heat the pizza on the high setting of the oven.
(c) The cost in electricity to heat the pizza if a kW h costs $0.16.

1. A certain satellite travels in an approximately circular orbit of radius 7.5 × 10⁶ m with a period of 6 h 27 min. Calculate the mass of its planet from this information

2. (a) At what height above Earth's surface is the energy required to lift a satellite to that height equal to the kinetic energy required for the satellite to be in orbit at that height? (b) For greater heights, which is greater, the energy for lifting or the kinetic energy for orbiting?

Please help:)

Elements that appear in the same column of the periodic table often share similar chemical properties. In the case of the alkaline earth metals, this is troublesome since the body treats calcium (necessary for proper bone growth) and radium (a radioatictive element) as chemically similar, storing both in bone marrow. The radium then bombards nearby bone cells with alpha particles, causing them to \"crumble.\" Radium poisoning investigations often center on the identification of radium and its isotopes in bone samples using a mass spectrometer. Pictured is a schematic of a simplified mass spectrometer, showing the paths of calcium, barium (another alkaline earth metal) and radium isotopes entering the chamber. The region shown is immersed in a constant magnetic field of 0.352 T pointing out of the plane of the schematic. Motion of the positively-charged isotopes toward the right was initiated by a potential difference of 3082 V on the two plates shown. Using the data shown in the table below, calculate the path radius of the Ca ion.

Two small metal cubes with masses 2.0 g and4.0 g are tied together by a 4.9-cm-long massless string and are at rest on a frictionless surface. Each is charged to +2.2 μC .

The string is cut. What is the speed of each sphere when they are far apart?
Hint: There are two conserved quantities. Make use of both.

The mechanical energy of the system is 0.89 J and the tension in the string is 18.1 N

A hiker starts at his camp and moves the following distances while exploring his surroundings: 74.0 m north, 2.20 ? 10² m east, 1.20 ? 10² m at an angle 30.0

how does the prescence of an idler gear affect the relationship between a driver gear and a driven gear in a gear train?

Inside a NASA test vehicle, a 3.50-kg ball is pulled along by a horizontal ideal spring fixed to a friction-free table. The force constant of the spring is 227 N/m . The vehicle has a steady acceleration of 5.00 m/s2, and the ball is not oscillating. Suddenly, when the vehicle's speed has reached 45.0 m/s, its engines turn off, thus eliminating its acceleration but not its velocity.

A. Find the amplitude.

B. Find the frequency of the resulting oscillations of the ball. (i already found the answer for this to be 1.28 Hz)

C. What will be the ball's maximum speed relative to the vehicle?

Where is the image in a plane mirror formed?

Your friend Noelle suggests the following hypothesis: "The image of an object formed by a plane mirror is formed on the surface of the mirror." Design an experiment to test Noelle's hypothesis.

Available equipment: Plane mirror, object, masking tape, paper, meter stick.

Design and describe the experiment that you plan to perform. Remember that your prediction of the outcome if the expirement must allow from the hypothesis you are testing. Then perform the experiment and record the outcome. Explain the outcome using a ray diagram. Discuss whether the outcome agrees or disagrees with the prediction. If it disagrees, how would you convince Noelle that her idea has been disproven?

Calculate the maximum rate at which a rocket can expel gases if its acceleration cannot exceed seven times that of gravity. The mass of the rocket just as it runs out of fuel is75800 kg, and its exhaust velocity is 2.00 ? 10³ m/s. Assume that the acceleration of gravity is the same as on the earth's surface (9.80 m/s²).

A cart with mass 330 g moving on a frictionless linear air track at an initial speed of 2.1 m/s undergoes an elastic collision with an initially stationary cart of unknown mass. After the collision, the first cart continues in its original direction at 1.05 m/s. 1.) What is the mass of the second cart? 2.)What is its (second cart) speed after impact? 3.)What is the speed of the two-cart center of mass?

Consider a small sized company that is interested in setting up a network for their business. The company has a total of 350 employees: 250 employees are located on five floors of the HQ building based in Chicago, and the other 100 employees are located on two floors in a building in Seattle. The two sites are connected using a WAN link. Each employee has a desktop and an IP phone on their desk. In each office (building), there are four servers, the first for engineering development, the second for manufacturing, the third for the company’s external website, and the fourth for management, sales, marketing, and personnel databases. The servers in the Seattle office are backup servers for the servers in the Chicago HQ; if any server fails in HQ, its functionality fails over to the corresponding server in Seattle. There should be three LANs, one for the engineering department, one for manufacturing department, and one for marketing and administration. The engineering department has 200 employees in total (150 in Chicago, 50 in Seattle), and its LAN hosts the engineering development server. The manufacturing department has 100 employees in total (70 HQ, 30 Seattle), and its LAN hosts the manufacturing server. The last LAN hosts the remaining two servers, and has 30 employees in Chicago and 20 employees in Seattle. All these LANs are wired LANs. Additionally, the Chicago office has a guest WLAN that can serve up to 63 connections, while the Seattle office has a guest WLAN which serves up to 30 connections. The company has been assigned the IP address range 216.244.168.0 to 216.244.175.255. The IP addresses 216.244.175.254 and 216.244.175.253 are reserved for the two end points of the WAN link.
1. Describe the networking requirements for this company as a Network Administrator.
2. Design a network and specify the IP address range for each LAN/WLAN.

3. Suppose an engineer in HQ opens a telnet session with the engineering development server (in HQ). Describe in detail the traffic flow.
4. Suppose an engineer in HQ pings the manufacturing server in the manufacturing LAN in HQ. Describe in detail the traffic flow.
5. Suppose an engineer in HQ pings the manufacturing server in the manufacturing LAN in Seattle. Describe in detail the traffic flow.
6. Write down the routing table of the router to which the engineering LAN is connected to in HQ. The routing information in this table should ensure network-wide IP connectivity between any pair of hosts. The table should include these fields: destination network address, netmask, next hop address/outgoing interface, hop count to destination (including the destination subnet).

1. An object is 30 cm in front of a converging lens with a focal length of 10 cm. Use ray tracing to

determine the location of the image. Is the image upright or inverted? Is it real or virtual?

2. An object is 6.0 cm in front of a converging lens with a focal length of 10 cm. Use ray tracing to

determine the location of the image. Is the image upright or inverted? Is it real or virtual?

3. An object is 20 cm in front of a diverging lens with a focal length of 10 cm. Use ray tracing to

determine the location of the image. Is the image upright or inverted? Is it real or virtual?

4. An object is 15 cm in front of a diverging lens with a focal length of 10 cm. Use ray tracing to

determine the location of the image. Is the image upright or inverted? Is it real or virtual?