A100 kg roller coaster car is located at the top of a hill where the height is 20 m. what is the velocity when it reaches the bottom of the hill? 5.5 m/s 11.2 m/s 16.7 m/s 19.8 m/s

19.8 m/s

Explanation:

Assuming the car starts from rest, initially when it is at the top of the hill all the mechanical energy of the car is just potential energy, given by:

where

m = 100 kg is the mass

g = 9.8 m/s^2 is the gravitational acceleration

h = 20 m is the height

Substituting,

At the bottom of the hill, all this energy has been converted into kinetic energy (because energy cannot be created or destroyed, but only transformed). Therefore, the kinetic energy of the car is:

where

m = 100 kg is the mass of the car

v is the speed of the car at the bottom of the hill

Re-arranging this equation, we can find the value of v:

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

continuous conducting path for current, power supply