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. March 2016

Rotational Motion

Q- A uniform solid disk rolls down an inclined plane. Find the minimum coefficient of static friction that will permit the disk to roll without slipping, if the angle of the incline is 300 with the horizontal.

Solution:

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Interference of light

Q- Determine the minimum nonzero thickness of soap film (n=1.33) that will result in

(a) constructive interference of the red Ha line (λ= 656.3nm),

(b) destructive interference of the blue Hγ line (λ= 434.0nm)

Solution:

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NLM & Momentum

Q1- A firecracker, of mass 16 grams, explodes into two pieces (one of 4 grams and the other of 12 grams). The 4 gram piece has velocity just after the explosion of 10 m/s to the left. Find the velocity of the other piece just after the explosion.(Requested by Jay F)

Q2- Consider a conical pendulum …

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Electro Magnetic Induction

You have the following components with you (1) a100 mH inductor (2) a piece of copper wire (3) a light bulb and Rs 50.00 which just happens to be enough to purchase any capacitor as Radio Shack.
(A) How would you design a device, from the tools you have available above, to be able to detect Wi-Fi si…

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NLM

Q1- A woman at an airport is towing her 15.0 kg suitcase at constant speed by pulling on a strap at an angle above the horizontal. She pulls on the strap with a 40 N force, and the friction force on the suitcase is 20.0 N.

(a) Draw a free-body diagram of the suitcase.

(b) What angle does the strap…

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Magnetic Field

Q- In a long cylindrical wire of radius a = 3.1 mm the current density varies with distance r from the axis as j (r) = j0 (r/a). Here r is the distance from axis and j0 = 310 A/m2 is a constant. Find magnetic field at (a) on the axis of wire (b) at distance a/2 from the axis and (c) at the surface o…

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Sound waves (Interference)

Q- Two speakers are driven by the same oscillator of frequency 200 Hz. They are located horizontally at a distance of 6 meters from each other. Barbara stands in front of one speaker very far away, and walks towards the speaker. How many times will she hear a minimum intensity as she walks from far …

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Rotational Motion

Q- A uniform rod PQ, mass m and length l is free to rotate in a vertical plane about a fixed horizontal axis passing through P. The rod is released from rest when PQ makes an angle 600 with the downward vertical. Find the magnitude of the force exerted by the rod on the pivot just after it is releas…

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Wave-Optics

Q- Two light waves of wavelength 620 nm are initially exactly in phase. The waves pass through to different media of indexes of refraction n1= 1.40 and n2= 1.60. What is the thickness L of each medium that will put the waves out of phase once they pass through the two media? What is the next greater…

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Motion In 1 D

Q- A man travels 50 miles. He spends half his time on horseback and half his time walking. When he rides horseback he travels 9 miles/hour, on foot 3.5 miles/hour. How long will it take him to complete his journey? How many miles does he travel by horse? How many miles does he travel on foot?(On req…

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Interference of light

Q- In a double slit experiment the distance between the slits is 5.00mm and the slits are 1.0m from the screen. Two interference patterns can be seen on the screen: one due to the light with the wavelength 480nm and the other due to the light with wavelength 600nm.  What is the separation on the scr…

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NLM - Pulley

Current Electricity

Q1- In the construction of an electrical circuit a 5.00 µF capacitor was accidentally used instead of the required 16.0 µF capacitor? What value capacitor must a technician add to correct this circuit without removing existing circuit elements? Must any connections be broken in the process?

Q2- T…

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Center of Mass

Q1- Find the center of mass of a uniform right circular solid cone of base radius a and height h.

Q2- Find the center of mass of a hemispherical shell of constant density with inner radius r1 and outer radius r2.

Solutions:

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Coulomb's law and field

Q1- A proton is released from rest where an electric field of 640 N/C exists. (a) what is the acceleration of proton? (b) how long does it take to reach a speed of 1.2*106 m/s (c) How much distance does it travel during this time.

Q2- Three point charges are placed on the vertises of a triangle as …

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Rotational Motion

Q- A rectangular signboard has a mass of 1050 kg, a height h = 1 m, and a width W = 4 m. It is held by a light rod of length 5 m that is perpendicular to a rough wall. A guy wire at 300 to the horizontal holds the sign to the wall. Note that the distance from the left edge of the sign to the wall is…

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Radioactivity

Q- Isotope 137 Cs of Cesium has a half life of 30 years. Suppose a distributor sells 5 grams of it in January 1, 2000. a) Write an equation with giving the number of grams of the isotope left "t" years after January 1, 2000. b) How many grams are present after 6 years?

Solution:

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Projectile Motion

Q- Using kinematics, you will be asked to calculate the initial velocity of the projectile by measuring the vertical drop, h, and the horizontal distance from the launcher, d, assuming the initial direction of the displacement is horizontal. Using the equations: xf = x0 + vx0t and yf = y0 + vy0t – 1…

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Magnetic Field

Q- Four long straight wires each carrying current I are placed at the corners of a square of side a. The wires are parallel to each other and normal to the plane of the square. The direction of the current in two adjacent wires is out of the page and that in the other two is into the page. Find magn…

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Hydrodynamics

Q- A hydraulic cylinder needs to push 5.5 gallons of fluid (water) per minute at 2000 psi (like pushing the fluid out of a syringe). How big is the outlet port where the fluid leaves the cylinder?

Solution:

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