HP and Weight, this might be a little confusing Options

[celicarocker]

this whole theory is going off something i remember someone saying before. not sure of the exact numbers, but it was something like "every 125lbs you take out adds 4hp" or something like that. anyway, the point is there is a direct correlation between weight and HP.

now onto my main point. people talk stuff like "car A will beat car B becuase they both have the same HP, but car A is lighter" so if car B was reduced to the weight of car A, it would be faster? like if car A is 1900lbs and 150hp, and car B is 2700lbs and 150hp, wouldnt they both be the same speed? its like that old trick question "which would fall faster, a pound of bricks or a pound of feathers" where they'd both fall the same speed. so wouldnt a 1900lb car with 150hp go as fast as a 2700lb car with 150hp?

does anybody get what im trying to say?

[CoSo]

this whole theory is going off something i remember someone saying before. not sure of the exact numbers, but it was something like "every 125lbs you take out adds 4hp" or something like that. anyway, the point is there is a direct correlation between weight and  HP.

now onto my main point. people talk stuff like "car A will beat car B becuase they both have the same HP, but car A is lighter" so if car B was reduced to the weight of car A, it would be faster? like if car A is 1900lbs and 150hp, and car B is 2700lbs and 150hp, wouldnt they both be the same speed? its like that old trick question "which would fall faster, a pound of bricks or a pound of feathers" where they'd both fall the same speed. so wouldnt a 1900lb car with 150hp go as fast as a 2700lb car with 150hp?

does anybody get what im trying to say?
[right][snapback]348742[/snapback][/right]

Your analogy is misleading. Without getting too indepth into the physics side of things, given the bricks and feathers, a net acceleration of 9.8 m/s is acted upon it downwards due to gravity. Thus for any given distance, they will both hit the ground at the same time (ignoring air resistance). However, with your two cars, they do not accelerate at the same rate (and this is the key). Given a car has 150 HP and weighs 1900 lbs (and I'm assuming your keeping torque constant between the two cars, too), the engine can only translate that into a certain amount of energy to drive the vehicle forward. Because this car is lighter, it can accelerate faster (using formulas for power, kinetic energy and acceleration/velocity). Thus the acceleration is a function of the vehicle's mass (ie, it is dependant on the car system, rather than an external acceleration due to gravity). So, the lighter car accelerates faster. Or something.

This post has been edited by CoSo: Oct 25, 2005 - 3:34 AM