Question 1063987: A ball traveling at 30 m/s has 900 J of kinetic energy. What is the mass of the ball?
Answer by addingup(3677)   (Show Source):
You can put this solution on YOUR website! KE = 0.5*(mv)2
900 = 0.5*(m*30)^2
900 = 450*m^2
900 = 450*^2 flip the equation to get the variable on the left side:
450*m^2 = 900
m^2 = 2
m^2 - 2 = 0
m = (0 ± sqrt(0^2 - 4(-2)))/2
= ( ± sqrt(8))/2:
m = sqrt(8)/2 or m = (-sqrt(8))/2
sqrt(8) = sqrt(2^3) = 2sqrt(2):
m = (2 sqrt(2))/(2) or m = (-2 sqrt(2))/(2)
(2 sqrt(2))/(2) = sqrt(2):
m = sqrt(2) or m = (-2 sqrt(2))/(2)
(2 (-sqrt(2)))/(2) = -sqrt(2):
m = sqrt(2) or m = -sqrt(2)
you are not looking for a negative number, so try sqrt(2) for your answer:
mass = 1.414
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