Magnifying Glass With the Image at Infinity: A lens of focal length 40 mm is used as a magnifier. The object being viewed is 5.3 mm long, and is positioned at the focal point of the lens. The user of the magnifier has a near point at 25 cm. What is the angular magnification of the magnifier?
A. 6.3
B. 5.6
C. 6.9
D. 7.5
E. 8.1
Answer: A
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According to Newton's laws, the planets orbit the Sun due to ________
Fill in the blank(s) with correct word
Potential of Point-Charges: Point charges +4.00 ?C and +2.00 ?C are placed at the opposite corners of a rectangle as shown in the figure. What is the potential at point B due to these charges? (k = 1/4??0 = 8.99 × 109 N ? m2/C2) 
A. 8.99 kV B. 11.2 kV C. 89.9 kV D. 899 kV E. 112 kV
Use a flux plot to estimate the rate of heat flow through the object shown in the sketch. The thermal conductivity of the material is 15 W/(m K). Assume no heat is lost from the sides.
GIVEN
The shape of object shown in the sketch
The thermal conductivity of the material (k) = 15 W/(m K)
The temperatures at the upper and lower surfaces (30°C & 10°C)
FIND
The rate of heat flow through the object (By means of a flux plot)
ASSUMPTIONS
No heat is lost from the sides and ends
Uniform thermal conductivity
Two dimensional conduction
Steady state
SKETCH
Two points on a merry-go-round are located at distances from the center r1 and r2, where r1 < r2 . While the merry-go-round is in the process of speeding up to operational speed, which of the following equations involving magnitudes of angular speed, angular acceleration, and tangential speed for these points is incorrect?
a. ?1 = ?2 b. ?1 = ?2 c. vt1 = vt2 d. All of the equations are correct.