Reference no: EM131887762
Question 1
Suppose a train whistle sounds at 1.20 kHz. Find the frequency you hear when the train is approaching at 27.0 m/s. Take the velocity of sound in the air at that temperature to be = 331 m/s.
Question 2
By what percentage does the density of an aluminium block decrease by heating it from 20°C to 440°C? Take the Coefficient of Linear Thermal Expansion of aluminium to be 24 x 10-6 m/m°C.
Question 3
A 50 mW laser produces 532-nm green light. What is the number of photons it emits each second? Take Planck's Constant, h = 6.63 ×108 J·s and the speed of light, c = 2.99792458 × 108m/ s.
Question 4
What is the value of the refraction index for a medium in which the speed of light is 2.15 × 108 m/s?
Question 5
There are two layers of glass, the first layer is crown glass and the second layer is flint glass. What is the critical angle for light passing through the two layers of glass? Take the Refractive Index for crown glass to be 1.52 and for flint glass to be 1.61.
Question 6
A polarizing filter is positioned so that its axis is at an angle of 88 degrees to a beam of completely polarized light. The intensity of the incoming light is 130 W/m2. What will be the light's intensity after passing it through the filter?
Question 7
An 80 kg skydiver with a density of 1050 kg/m3 is in free fall. Calculate the buoyancy force due to the air and compare it with the weight of the skydiver using the ratio of weight vs. buoyancy force. Take the density of air as 1.28 kg/m3.
Question 8
An Airbus passenger aircraft lifts off the runway at a speed of 65 m/s. Assume that the speed of the air across the bottom of the wings is also 65 m/s. The mass of the aircraft is 210,000 kg. The total surface area of the wings is 415 m2. The density of the air is 1.28 kg/m3.
Calculate the speed of the air flowing across the top of the wings that will allow the aircraft to lift off and fly. Note that the elevation difference between the sides of the wings is small and can be ignored.
Question 9
Plaque build-up has decreased the inner diameter of a person's artery. If the person's initial systolic blood pressure was 130 mm Hg, what systolic pressure is required to maintain the blood flow when the artery size is reduced by 7%?
Question 10
A man is standing on the jetty at the edge of a lake. He wishes to direct the beam from his torch, which is 2.5 metres above the water, so that the beam reflects off the water and strikes a yacht on its side, 1.5 metres above the waterline. The yacht is at a distance of 25 metres from the water's edge. At what distance from him should the man aim his torch?
Question 11
A rectangular glass block (n = 1.53) lies submerged at the bottom of a tank of water. A light beam enters the water from the air above, making a 20° angle to the normal in the air. The Refractive Index of air is 1.00 and that of water is 1.33.
Determine the angle the light ray makes with the normal in the:
(a) Water
(b) Glass
Question 12
Due to the operational conditions and temperature gradient, a 70 mm diameter, 1.55 m long steel rod within a machine assembly is subjected to a combination of tensile loading of 150 N and thermal loading which imposes a longitudinal force of 230 N. The total loading results in an even distribution of forces on the body of the rod causing it to change its dimensions by increasing 0.5 mm in length at both ends and decreasing by 0.0125 mm at the diameter.
Determine the following:
(a) Total normal stress which the rod is subjected to.
(b) Total axial strain which the rod is subjected to.
(c) Total lateral strain which the rod is subjected to.
(d) What is the total length of the rod due to the effects of the combined loading?
(e) What is the new diameter of the rod due to the effects of the combined loading?
(f) What was the percentage total elongation of the rod?
(g) What was the percentage total reduction in the cross-sectional area of the rod?
(h) Poisson's Ratio, v, may be determined by dividing the negative value of the lateral strain by the axial strain. What is Poisson's Ratio for the rod material? Is this an acceptable amount for the rod?
(i) The Shear Modulus, G, of a material may be determined by the following equation: G = E/ 2(1 + ν), where E is the Modulus of Elasticity, and ν, is Poisson's Ratio. If the Modulus of Elasticity for the rod material is E = 195 GPa, what is the value of the Shear Modulus?
Question 13
A concave mirror has focal length 41 cm. Where should you place an object to get a real image at:
(a) 66.6 cm from the mirror?
(b) 1.5 m from the mirror?
Question 14
A brass rod hangs vertically from a fixed support. The rod is 1.9 m long and 1.45 mm in diameter.
(a) What mass hung from the rod will stretch it by 0.33 mm? Take EBrass= 117 GPa
(b) In practice, would we be able to place the mass (calculated at (a)) on top of the rod instead? If we did so, what, if any, would be the change in length of the rod?