Answer:
The torque about his shoulder is 34.3Nm.
The solution approach assumes that the weight of the boy's arm acts at the center of the boy's arm length 35cm from the shoulder.
Explanation:
The solution to the problem can be found in the attachment below.
Answer:

The splitting up of light into its constituent colours while passing from one medium to the other is called dispersion.
Answer:
-0.233 m left of diverging lens and ( 0.12 - 0.233 ) = -113 m left of conversing
and
0.023 m right of diverging lens
Explanation:
given data
focal length f2 = 14 cm = -0.14 m
Separation s = 12 cm = 0.12 m
focal length f1 = 21 cm = 0.21 m
distance u1 = 38 cm
to find out
final image be located and Where will the image
solution
we find find image location i.e v2
so by lens formula v1 is
1/f = 1/u + 1/v ...............1
v1 = 1/(1/f1 - 1/u1)
v1 = 1/( 1/0.21 - 1/0.38)
v1 = 0.47 m
and
u2 = s - v1
u2 = 0.12 - 0.47
u2 = -0.35
so from equation 1
v2 = 1/(1/f2 - 1/u2)
v2 = 1/(-1/0.14 + 1/0.35)
v2 = -0.233 m
so -0.233 m left of diverging lens and ( 0.12 - 0.233 ) = -113 m left of conversing
and
for Separation s = 45 cm = 0.45 m
v1 = 1/(1/f1 - 1/u1)
v1 =0.47 m
and
u2 = s - v1
u2 = 0.45 - 0.47 =- 0.02 m
so
v2 = 1/(1/f2 - 1/u2)
v2 = 1/(-1/0.14 + 1/0.02)
v2 = 0.023
so here 0.023 m right of diverging lens
It's called sedimentation. And erosion is when the rock is worn away by the water, and wind and becomes sediment.