Mass, m = 85 kg, velocity = 15 m/s, radius = 20m.

Centripetal force = mv²/r

F = 85*15²/20 = 85*15*15/20 = **956.25 N**

Dimensional Formula of Density

The dimensional formula of density is given by,

[M1 L-3 T0]

Where,

M = Mass

L = Length

T = Time

Derivation

Density (ρ) = Mass × Volume-1 . . . . . (1)

The dimensional formula of volume = [M0 L3 T0] . . . . (2)

And, the dimensional formula of mass = [M1 L0 T0] . . . . (3)

On substituting equation (2) and (3) in equation (1) we get,

Density = Mass × Volume-1

Or, (ρ) = [M1 L0 T0] × [M0 L3 T0]-1 = [M1 L-3 T0]

Therefore, density is dimensionally represented as [M1 L-3 T0].

Hope i helped!

**Answer:**

Power = Energy transferred / time

**Explanation:**

Let u = the vertical speed at launch, m/s

g = 9.8 m/s², acceleration due to gravity.

Part (a)

After 2.4 s, the vertical speed is 10 m/s.

Therefore

(10 m/s) = (v ft/s) - (9.8 m/s²)*(2.4 s)

v = 10 + 9.8*2.4 = 33.52 m/s

Answer: 33.52 m/s upward

Part (b)

After 5.1 s, the vertical speed is

(33.52 m/s) - (9.8 m/s²)*(5.1 s) = -16.46 m/s.

This means that the rock reached the maximum height and began falling downward.

Answer: 16.46 m/s downward