How does a planetary nebula form
What will be an ideal response?
Answer: Episodes of thermal runaway in the helium-burning shell of a low-mass star push the envelope of the star off into space. The expelled enveloped forms a planetary nebula.
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A constant force of 15 N in the negative y direction acts on a particle as it moves from the origin to the point 
m. How much work is done by the given force during this displacement?
A. +45 J B. ?45 J C. +30 J D. ?30 J E. +75 J
A nearsighted person has a near point of 12. cm and a far point of 17. cm. If the lens is 2.0 cm from the eye: (a) what lens power will enable this person to see distant objects clearly? (b) what then will be the new near point?
What will be an ideal response?
A coating is being applied to reduce the reflectivity of a pane of glass to light with a frequency of 5.75 × 1014 Hz that is incident normally on the pane
If the material has an index of refraction of 1.375 and the glass has an index of refraction of 1.537, what is the minimum thickness the coating should have? (c = 3.00 × 108 m/s) A) 60.0 nm B) 80.1 nm C) 65.2 nm D) 145 nm E) 94.9 nm
An x-t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 6 s the velocity of the ball is zero. We can be positive that at t = 6 s,
a. the slope of the curve is non-zero. b. the acceleration is constant. c. the ball has stopped. d. none of the above answers is always correct.