The new EV-1 electric car makes use of storage batteries as its source of energy. Its mass is 1300 kg and it is powered by 26 batteries, each 12 V, 52 A•h. assume that the car is driven on the level at an average speed of 40 km/hr and the average friction force is 240 N. Assume 100% efficiency and neglect energy used for acceleration. Note that no energy is consumed when the vehicle is stopped since the engine doesn’t need to idle.
(a) Determine the horsepower required.
(b) After approximately how many kilometers must the batteries be recharged?
2007-12-11 16:28:54 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The total energy stored by the batteries is
( 26 ) ( 12 V ) ( 52 A-h ) ( 3600 s / h ) Joules.
This energy is consumed at a rate computed by multiplying the friction force over the distance traveled per second at 40 kph:
( 240 N ) ( 40 km / h ) ( 1000 m / km ) ( 1 h / 3600 s ) ( 1 sec ) Watts.
The usual conversion between Watts ahd horsepower is
1 hp = 746 Watts.
The energy consumed per kilometer is
( 240 N ) ( 1000 m ) Joules.
Divide that into the total energy provided to see how many kilometers you get.
2007-12-11 16:41:59 · answer #1 · answered by jgoulden 7 · 0⤊ 0⤋