Answer:
The focal length of the lens must be 27.3cm
Explanation:
Image distance= -75 cm
Object distance= 20.0cm
From:
1/v + 1/u = 1/f
-1/75+ 1/20 = 1/f
11/300= 1/f
f= 300/11
f= 27.3cm
The focal length of the lens must be 27.3cm
It's D. Gravity holds everything in place
W = mg
Weight on Earth = 50 x 9.8
= 490 N
Weight on Mars = 50 x 3.7
= 185 N
