Answer:
470 N.
Explanation:
Using equations of motion:
S = vi*t + 1/2*(a*(t^2))
Given:
S = 0.65 m
t = 1.5 s
vi = 0 m/s
0.65 = 1/2 * (a * (1.5)^2)
a = 1.3/2.25
= 0.578 m/s^2
Force = mass * acceleration due to gravity
= 92 * 0.578
= 53.16 N
Total force = 420 + 53.16
= 473.16 N
= 470 N.
If they're brought closer together
Answer:
Object should be placed at a distance, u = 7.8 cm
Given:
focal length of convex lens, F = 16.5 cm
magnification, m = 1.90
Solution:
Magnification of lens, m = -
where
u = object distance
v = image distance
Now,
1.90 = 
v = - 1.90u
To calculate the object distance, u by lens maker formula given by:
u = 7.8 cm
Object should be placed at a distance of 7.8 cm on the axis of the lens to get virtual and enlarged image.