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Power

Work done in joules

A block of mass 5kg is lifted 2 meters in 3 seconds. Compute the work done in joules and in ergs.

Current & Resistance

1. An ant is 3 cm from a magniflying lens with a focal length of 5 cm. The image of the bug is A. real, upright, enlarged, other side of lens B. virtual, upright, enlarged, same side of lens C. virtual, smaller, inverted, same side of lens D. real, upright smaller, other side of lens A 5kW h

Wave properties of particles

The resolving power of a microscope is proportional to the wavelength used. A resolution of approximately 1.0 x 10-11 m (0.01 nm) would be required in order to "see" an atom. (a) If electrons were used (electron microscope), what minimum kinetic energy would be required for the electrons? (b) If phtons were used, what minimum p

Conducting Rod

A conducting rod of length l moves on two horizontal, frictionless rails, as shown in the attached file 'Figure P31.20'. If a constant force of 1.00 N moves the bar at 2.00 m/s through a magnetic field B that is directed into the page, (a) What is the current through the resistor R? (b) What is the rate at which energy is d

Finding work using time dependent Force function.

I only need the last five parts explained to me. See attached PDF file for the question ! Homework 5-1 Due date: Mon 22 Mar 2004 09:00:00 AM MST 18 point(s) Pulling Out Tree Stump You are in a truck trying to pull out a tree stump. The mass of the tree stump m is 170.0 kg. You have attached the winch at the f

Momentum, Velocity and Power

1. A 1500kg automobile starts from rest on a horizontal road and gains speed of 72km/h in 30 s. a) What is the average power required of the car at the end of the 30 s? b) What is the average power required of the car during the 30 s interval? c) What is the instantaneous power at the end of the 30 s interval, assuming t

Current and Power in a Resistor

A 60.0 ohm resistor is connected in parallel with a 115.0 ohm resistor. This parallel group is connected in series with a 15.0hm resistor. The total combination is connected across a 15.0-V battery. Find the current and power in the 115 ohm resistor.

Motion in two dimensions

I have been struggling with this problem for two days. I tried to apply the basic kinematic equations to the problem but couldn't figure it out

Power and Voltage

What happens to the power used by an electric appliance if the voltage across this appliance is decreased to half of the original value?

Solve: Magnetic Field on a Compass

Question: A power line is 3.5m off the ground and is carrying 75 amps. A man standing under the power line is holding a compass 1.25m off the ground. 1) How large is the magnetic field produced on the compass by the power line? 2) If the power line runs east and west, how does its magnetic field affect the direction in whi

Raising a yacht from the seabed by attaching filled air bags to it

A large yacht has a mass of 305 tonnes. The yacht sinks and is lying on the sea bed at a depth of 40m. It is estimated that the volume of teh yacht is such that it displaces 0.8m3 of water when it is totally submerged under water. A salvage team decides to raise the yacht to the surface by fixing large bags to the yacht and

Calculating radiated power of a firecracker

The explosion of the firecracker in the air at a height of 40m produces a 100 db sound level at the ground below. If the threshold of hearing is 10-12Wm-2, what is the instantaneous total radiated power, assuming that it radiates as a point source?

Find the minimum power required in an electricity generating station.

An electricity generating station has a rated output of 300 megawatts. Given that the station heat rate is 12 000kJ/kW-h, and the coal used has a heat value of 23 000kJ/kg, find the minimum possible belt-drive power required for the bunker coal conveyor in order to keep the boiler supplied when the station is on full load. The

Force between charges that are apart in air

Factor of k for air is 8.93x10(power)9 Nm(power)2/C(power)2 Calculate force between charges of +150.0(micro)C and -75.0(micro)C that are 0.600 m apart in air. * I am not able to use the proper symbols for (power), or (micro)

Electromagnetic Induction

Imagine in a remote area of the countryside a 70-kV, 60-Hz power line. A shifty local resident has erected a large open loop just below the line with the intention of drawing power. Is this possible and, if so, how would it be transferred? Where would the energy stolen come from? Would anyone be able to detect the loss? Might it

Circuits

Multiple choice: 1. An ideal source of emf is connected in seriew with a resistor in closed loop, and a current or 0.e50 A circulates. An additional 6.0-Ohm resistor is added in series, and the current drops to 0.30 A. The original resistance was: (a) 9.0 Ohm (b) 6.0 Ohm (c) 15 Ohm (d) 3.0 Ohm (e) none of these. Explain your ch

Magnetic flux...induced emf...etc...

Consider a rectangular loop of length l (parallel to x) width w (parallel to y) total resistance R, is being pulled at constant force F=fx. If at tiem t=0 it is aligned with the front edge at x=0, has velocity vx, and the magnetic field everywhere is B= 0 x<0 B= BoZ x>0 solve and draw plots for the time dependence of: