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(8c8p74) A 1.70 kg water balloon is shot straight up with an initial speed of 3.

ID: 1782722 • Letter: #

Question

(8c8p74) A 1.70 kg water balloon is shot straight up with an initial speed of 3.45 m/s. What is the kinetic energy of the balloon just as it is launched? Submit Answer Tries 0/12 How much work does the weight of the balloon do on the balloon during the balloon's full ascent? Submit Answer Tries 0/12 What is the change in the gravitational potential energy of the balloon-Earth system during the full ascent? Submit Answer Tries 0/12 If the gravitational potential energy is taken to be zero at the launch point, what is its value when the balloon reaches its maximum height? Submit Answer Tries 0/12 If, instead, the gravitational potential energy is taken to be zero at the maximum height, what is its value at the launch point? Submit Answer Tries 0/12 What is the maximum height of the balloon? Submit Answer Tries 0/12

Explanation / Answer

m = mass = 1.70 kg

vi = initial velocity of launch = 3.45 m/s

initial KE at the time of launch = (0.5) m vi2 = (0.5) (1.70) (3.45)2 = 10.12 J

using conservation of energy

work done by weight = initial KE at the time of launch = 10.12 J

using conservation of energy

change in gravitational PE = - change in KE = - (KFf - KEi) = - (0 - 10.12) = 10.12 J

PEf - PEi = 10.12

PEf - 0 = 10.12

PEf = 10.12 J

PEf - PEi = 10.12

0- PEi = 10.12

PEi = - 10.12 J

mgh = 10.12

1.7 x 9.8 h = 10.12

h = 0.61 m