Doubling the aperture diameter of a camera lens will change the light intensity admitted to the film by what factor?
a. 4.0
c. 0.50
b. 0.25
d. 2.0
A
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Slanting Surfaces With Friction: The figure shows a block of mass m resting on a 20° slope. The block has coefficients of friction ?s = 0.64 and ?k = 0.54 with the surface of the slope. It is connected using a very light string over an ideal pulley to a hanging block of mass 2.0 kg. The string above the slope pulls parallel to the surface. What is the minimum mass m so the system will remain at rest when it is released from rest?
A. 2.1 kg B. 3.3 kg C. 1.3 kg D. 3.6 kg
Self-Inductance: The figure shows a solenoid having no appreciable resistance. When the current in this solenoid is decreasing at a rate of 5.5 A/s, the self-induced emf in the solenoid is measured to be 9.5 V.(a) What is the self-inductance of this solenoid?(b) If the current is in the direction from b to a in the figure, which point, a or b, is at higher potential?
What will be an ideal response?
The reason the rings of Saturn exist is because
A) the ring material lies within the Roche limit of Saturn. B) the gravitational influence of Titan confines them to those orbits. C) the eruptions of Mimas' volcanoes are keeping them supplied with ice. D) there has not been sufficient time for the ring particles to form a moon. E) Saturn's rapid rotation is spinning material away from its equator, out into space.
Rita raises a 10kg package to a height of 2.5 m in 2.0 s
(a) How much work did she do on the package? (b) How much power was expended on the package? (c) If she were to raise the package in 1.0 s rather than 2.0 s, how do the work and power change?