Author Question: How far from a lens of focal length 50.0 mm must the object be placed if it is to form a virtual ... (Read 13 times)

jrubin · **on:** Jul 27, 2018

How far from a lens of focal length 50.0 mm must the object be placed if it is to form a virtual image magnified in size by a factor of three?

A) 33.3 mm
B) 48.0 mm
C) 38.3 mm
D) 42.2 mm
E) 54.4 mm

Question 2

A ballerina spins initially at 1.5 revolutions/second when her arms are extended. She then draws in her arms to her body and her moment of inertia becomes 0.88 kg-m2 and her angular speed increases to 4.0 rev/s.

Determine her initial moment of inertia.