Answer:
Explanation:
height of pole = 15 ft
height of man = 6 ft
Let the length of shadow is y .
According to the diagram
Let at any time the distance of man is x.
The two triangles are similar

15 y - 15 x = 6 y
9 y = 15 x

Differentiate with respect to time.

As given, dx/dt = 4 ft/s

ft/s
Answer:
When an object is balanced, about a pivot, the total clockwise moment must be equal to the total anticlockwise moment about that pivot.
Hope that helps.
Answer:
B. Its density is lower than that of water
Explanation:
density = mass / volume
density of the liquid = 85 / 100 = 0.85 g/cm^3
now,
density of water is 1 g/cm^3 which is greater than the density of the given liquid ( 0.85 g/cm^3 )