A13 g rubber stopper is swung in a horizontal circle with a radius of 0.85 m with a period of 0.65 s. (a) how fast is the stopper moving? (b) what is the centripetal acceleration of the stopper? (c) find the centripetal force that is exerted on the stopper.

Explanation:

(a) v = 2π r / t

v = 2π (0.85 m) / (0.65 s)

v = 8.2 m/s

(b) a = v² / r

a = (8.2 m/s)² / (0.85 m)

a = 79 m/s²

(c) F = ma

F = (0.013 kg) (79 m/s²)

F = 1.0 N

their crystal patterns have been disrupted by stress

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day