Aball is dropped from rest and falls to the floor. the initial gravitational potential energy of the ball-earth-floor system is 10 j. the ball then bounces back up to a height where the gravitational potential energy is 7 j. what was the mechanical energy of the ball-earth-floor system the instant the ball left the floor? (a) 0j (b) 3j (c) 7j (d) 10j

C is the right option

Explanation:

The ball looses energy in the rebound due to ball deformation, heat loss from bounce. Total mechanical energy is not conserved so mechanical energy as it bounces of the floor is equal to transformed potential energy at maximum height of second bounce which is 7j.

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