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two cars are moving. the first car has twice the mass of the second car but only

ID: 1344389 • Letter: T

Question

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 8.43 m/s, they then have the same kinetic energy. calculate the original speeds of the two cars. Speed of car 1? Speed of car 2? 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 8.43 m/s, they then have the same kinetic energy. calculate the original speeds of the two cars. Speed of car 1? Speed of car 2? Speed of car 1? Speed of car 2?

Explanation / Answer

here

m1 = 2 * m2
Ek1 = 0.5Ek2
0.5 * m1 * (v1)² = 0.5 * [0.5 * m2 * (v2)²]
By substitution we get:
0.5 * (2 * m2) * (v1)² = (1/4) * m2 * (v2)²
v2 = 2 * v1

With increased speed, we have:
Ek1 = Ek2
0.5 * m1 * (v1 + 8.43)² = 0.5 * m2 * (v2 + 8.43)²
Then by substitution we get:
0.5 * (2 * m2) * (v1 + 8.43)² = 0.5 * m2 * (2 * v1 + 8.43 )²
v1 = 8.43 / sqrt(2) = 5.96 m/s

v2 = 2 * v1 = 11.92 m/s