Physics
posted by Em on .
Two cars are moving. The first car has twice the mass of the second car but only half as much kinetic energy. When both cars increase their speed by 3.41 m/s, they then have the same kinetic energy.
a) What is the original speed of the first car?
b)What is the original speed of the second car?

M1 = 2M2
M1*V1^2 = (1/2)M2*V2^2 = (M1/4)V2^2
V2 = 2 V1
M1*(V1+3.41)^2 = M2*(V2+3.41)^2
= (M1/2)*(2V1 +3.41)^2
Cancel the M1's and solve this quadratic equation for V1:
(V1 +3.41)^2 = (1/2)(2V1 + 3.41)^2