Other Physics Answers

In the Bohr model, the electron is in constant motion. How can such an electron have a negative amount of energy?

What is the shortest wavelength present in the Brackett series of spectral lines?

This question is about forces and moments of forces.

a. (I) Define the moment of a force about a point

(II) State the law of moments as a condition for equilibrium

b. A crane has a jib (AC) of mass 2500kg pivoted at A. 

The jib is supported by a horizontal cable BC. The centre of mass of the jib its at D. The dimensions are as shown on the diagram.

(I) Make a sketch copy of the diagram and on it draw three arrows to represent the three forces acting on the jib.

(ii) Calculate the tension in the cable BC.

C. The end of the jib C is raised by shortening BC. Explain whether the tension in BC will increase or decrease. 

Consider two steel balls. Ball 1 has a

weight of 1.5 N. Ball 2 has a weight

of 15 N. Both balls are released

simultaneously from a height of 2.0 m.

Which ball hits the ground first?

a) Ball 1 hits the ground first.

b) Ball 2 hits the ground first.

c) Both balls hit the ground at the

same time.

d) It can’t be determined from the

information provided.

I think the answer is (b).

Am I right?

4. A cylinder contains a hydrogen gas of volume 2.40  10−3 m3 at 17 C and 2.32 

106 Pa. Calculate

a. the number of moles of hydrogen in the cylinder,

b. the number of molecules of hydrogen in the cylinder,

c. the mass of the hydrogen (given the molar mass of hydrogen = 2 g mol−1).

a pipe of radius 7m contain natural oil of density 800 and moves at velocity 25m/s the pipe is branched into 2 tubes of A and B if ra equal 2m and rb equal 4m also va equal 10m/s if there was a leakage in the pipe of flow 2m³/s what's the mass of flowing in the pipe in 10 min and what is the velocity of the tube B

STUDY OF ATTENUATION AND PROPAGATION CHARACTERISTICS OF OPTICAL FIBER CABLE I . ATTENUATION IN FIBERS Aim (i) To determine the attenuation for the given optical fiber. (ii) To measure the numerical aperture and hence the acceptance angle of the given fiber cables. Apparatus Required Fiber optic light source, optic power meter and fiber cables (1m and 5m), Numerical aperture measurement JIG, optical fiber cable with source, screen. Principle The propagation of light down dielectric waveguides bears some similarity to the propagation of microwaves down metal waveguides. If a beam of power Pi is launched into one end of an optical fiber and if Pf is the power remaining after a length L km has been traversed , then the attenuation is given by, Attenuation = 10[ log (Pi/Pf)]/L dB /km Formula Attenuation = 10[ log (Pi/Pf)]/L dB /km Fig.5.1 Setup for loss measurement Fiber Cable AC Fiber Optic Light Sour

Another student wishes to

Water.

-3

check the conclusion by repeating the experiment with

12.5 cms of cold

Suggest two con itions which he should keep the same so that the comparison will be fair

A solid sphere of mass 2.0 kg and radius 0.75 m about a diameter

A horse pulls a wagon with a force of 50 N at an angle of 37o with the horizontal and moves along at a speed of 6 km/hr. (a) How much work does the horse do in 10 minutes? (b) What is the power output of the horse?