The engine in an imaginary sports car can provide constant power to the wheels over a range of speeds from 0 to 70 miles per hour (mph). At full power, the car can accelerate from zero mph to 29.0 mph in time 1.20s .
At full power, how long would it take for the car to accelerate from 0 to 58.0 mph? Neglect friction and air resistance.
So I'm under the impression that I need to a use a relation between power and energy, and energy and velocity....
I've determined the velocity to be 1.3 m/s. Only problem now is that the only way I can connect the formulas is through mass, which is not given. Any ideas?
2007-03-05 19:43:30 · 3 answers · asked by Dathan C 2 in Science & Mathematics ➔ Physics
Helmut has the correct answer, i had the same problem and did it their way and got the correct answer, for part b you would the first person's answer or double the time it takes to go from 0-29
2007-03-06 16:01:43 · answer #1 · answered by Anonymous · 2⤊ 1⤋
Constant power means constant acceleration. This means that the speed changes by the same amount in a unit time.
So if it takes 1.20 seconds to go from 0 to 29, then it takes 1.20 seconds to go from 29 to 58.
Total time = 2.40 seconds
2007-03-05 19:48:04 · answer #2 · answered by Gnomon 6 · 2⤊ 8⤋
E = ∫Pdt = Pt for constant power.
(1/2)m(29^2) = 1.2P
P = 350.4166666666666666667m
(1/2)m(58^2) = 350.4166666666666666667mt
t = 4.8 s
2007-03-05 20:40:15 · answer #3 · answered by Helmut 7 · 6⤊ 4⤋