A sports car traveling along a straight line increases its speed from 19.7 mi/h to 59.7 mi/h. What is the ratio of the final to the initial magnitude of its momentum?
What is the ratio of the final to the initial kinetic energy?
2007-03-18 09:43:42 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Momentum p = mv.
So the ratio of the momentums is simply the ratio of the speeds ie 59.7:19.7
Kinetic energy KE = (1/2)*m*v^2
The ratio of the KEs is the ratio of the speeds squared ie (59.7)^2 : (19.7)^2
2007-03-18 09:48:32 · answer #1 · answered by dudara 4 · 1⤊ 0⤋
Since momentum = Mv, the ratio of the final to the initial magnitude of the car's momentum is v(final) to v(initial), that is
59.7 : 19.7 or 3.03... : 1.
Since kinetic energy is (1/2)Mv^2, the ratio of the final to initial kinetic energy is [v(final)]^2 to [v(initial)]^2, that is
(59.7)^2 : (19.7)^2 = (3.03...)^2 : 1 = 9.18... : 1.
Live long and prosper.
2007-03-18 09:57:02 · answer #2 · answered by Dr Spock 6 · 0⤊ 0⤋