You are rearranging the furniture in your living room. In doing so, you push a 30 kg sofa to the left a total distance of 2 m and then you push it back to the right a distance of 1 m. The coefficient of kinetic friction between the sofa and the hardwood floor is 0.2. (a) What is the work done by friction in moving the sofa? (b) Suppose that you had instead simply moved the sofa to its final position by moving it directly 1 m to the left. What is the work done by friction in this case? (c) From the results you obtained in parts (a) and (b), what can you conclude about the nature of the friction force? Is it a conservative force? Explain.
You are rearranging the furniture in your living room. In doing so, you push a 30 kg sofa to the left a total distance of 2 m and then you push it back to the right a distance of 1 m. The coefficient of kinetic friction between the sofa and the hardwood floor is 0.2. (a) What is the work done by friction in moving the sofa? (b) Suppose that you had instead simply moved the sofa to its final position by moving it directly 1 m to the left. What is the work done by friction in this case? (c) From the results you obtained in parts (a) and (b), what can you conclude about the nature of the friction force? Is it a conservative force? Explain.
You are rearranging the furniture in your living room. In doing so, you push a 30 kg sofa to the left a total distance of 2 m and then you push it back to the right a distance of 1 m. The coefficient of kinetic friction between the sofa and the hardwood floor is 0.2. (a) What is the work done by friction in moving the sofa? (b) Suppose that you had instead simply moved the sofa to its final position by moving it directly 1 m to the left. What is the work done by friction in this case? (c) From the results you obtained in parts (a) and (b), what can you conclude about the nature of the friction force? Is it a conservative force? Explain.
two satellites are in circular orbits around the Earth. Satellite A is at an altitude equal to the Earth's radius, while satellite B is at an altitude equal to twice the Earth's radius. What is the ratio of their periods, Tb/Ta
Fresnel lens: You would like to design a 25 mm diameter blazed Fresnel zone plate with a first-order power of
+1.5 diopters. What is the lithography requirement (resolution required) for making this lens that is designed
for 550 nm? Express your answer in units of μm to one decimal point.
Fresnel lens: What would the power of the first diffracted order of this lens be at wavelength of 400 nm?
Express your answer in diopters to one decimal point.
Eye: A person with myopic eyes has a far point of 15 cm. What power contact lenses does she need to correct
her version to a standard far point at infinity? Give your answer in diopter to one decimal point.
Paraxial design of a field flattener. Imagine your optical system has Petzal curvature of the field with radius
p. In Module 1 of Course 1, a homework problem asked you to derive the paraxial focus shift along the axis
when a slab of glass was inserted in a converging cone of rays. Find or re-derive that result, then use it to
calculate the paraxial radius of curvature of a field flattener of refractive index n that will correct the observed
Petzval. Assume that the side of the flattener facing the image plane is plano. What is the required radius of
the plano-convex field flattener? (p written as rho )
Chapter 7 Solutions
College Physics Volume 1 (Chs. 1-16); Mastering Physics with Pearson eText -- ValuePack Access Card -- for College Physics (10th Edition)
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