Physics Answers

Two charges are on the x-axis. Charge q1 = +25 nC is at x = 4.00cm while charge q2 = -75nC is at x = 7.00 cm,

Find the magnitude and direction of:

a.) the electric force that q1 exerts on q2; and

b.) the electric force the q2 exerts on q1.

Illustration:

Free-body diagram:

a steel plug has a diameter of 5cm at 30°c .atehat temperature will it fit exactly into a hole of constant diameter 4.997cm ( coefficient of liner expansion of stee is 11×10-60C-1

Name of the device 

Energy Transformation 

Wind-Up torch 

Match-Catching light 

Metal bubbling in solid 

Balloon being inflated 

Handle-turned generator and a bulb 

Battery and an electric bell 

A rain drop from 500m is not likely to attain a velocity of 100m/s2 explain.

A square field measuring 100.0 m by 100.0 m has an area of 1.00 hectare. An acre has an area

of 43,600 ft2

. If a country lot has an area of 12.0 acres, what is the area in hectares?

derive an expression for planck's law of blackbody radiation using this law of wien's displacement law and stefan boltzmann law

SHOW SOLUTION:

1. Compute the resistance of a conductor given a resistivity of 10.4Ωm, length of 4m, and a diameter of 20mm.

2. A length of a gold wire (α = 3.4 x 10^

-3) has a resistance of 10 ohms at 25 degrees Celsius. Calculate resistance if the temperature rises to 90 degrees Celsius.

SHOW SOLUTION:

1. Compute the resistance of a conductor given a resistivity of 10.4Ωm, length of 4m, and a diameter of 20mm.

2. A length of a gold wire (α = 3.4 x 10^

-3) has a resistance of 10 ohms at 25 degrees Celsius. Calculate resistance if the temperature rises to 90 degrees Celsius.

A Diesel cycle operates with a compression ratio of 13.5 and with a cutoff

occurring at 6% of the stroke. State 1 is defined by 14 psia and 140 F. For the hot air

standard with k=1.34 and for an initial volume of 1 cu.ft. compute a) Qr, BTU, b)

Wnet, BTU, c) thermal efficiency, %, d) mean effective pressure, psi. e) For a rate of

circulation of 1000 cubic feet per minute, compute the horsepower

An ideal Otto engine, operating on the hot-air standard with k=1.34, has a

compression ratio of 5. At the beginning of compression the volume is 6ft3

, the

pressure is 15 psia and temperature is 100F. during constant – volume heating , 500

Btu are added per cycle. Compute Wnet, Qr, thermal Efficiency, and mean

effective pressure.