# Finding the Force of air resistance

• scytherz
In summary, the 1967 Corvette with a weight of 3020 lbs and a 427 cu-in engine rated at 435 hp at 5400 rpm, would attain a speed of 120 mph after 6 seconds if the engine uses all 435 hp at 100% efficiency during acceleration. The average acceleration would be 0.91g. Approaching the problem using the formula for kinetic energy, the correct answer is 53 m/s or 119 mph. It was initially thought to be a more complex problem, but the solution was actually much simpler.
scytherz
A 1967 Corvette has a weight of 3020 lbs. The 427 cu-in engine was rated at 435 hp at 5400 rpm. a) If the engine used all 435 hp at 100% efficiency during acceleration, what speed would the car attain after 6 seconds? b) What is the average acceleration? (in “g”s).

ans...
a) 120 mph b) 0.91g.

If someone knew how to approach this problem, kindly tell to me... Since I've tried different approaches, (Finding the Force of air resistance, rolling friction, Fuel consumption, substituting the energy used by the gasoline as the kinetic energy, .. But still didnt found the answer,... its almost 1 and half a week, trying to solve this problem,... and I think my approach is going way off...

Relevant Equations:

P = W/t
K=1/2mv^2
1 hp = 746 W = 550 ft lb/s
1 L = 3.5x10^7

The attempt at solution

since the car uses 427 in^3 engine(6.997 L), since 1L of using gasoline is 3.5x10^7, so the energy used is 244 895 000 j divide by 6 s, is 40 815 833.33j/s subtracted by the 435/6 hp, ans 40761 748.33 j/s... using the formula for Kinetic energy, K= 1/2mv2, I got 243 m/s... which is wrong...

I also tried using P = W/t , by finding the work, w= pt, w= 1 947 060 Nm, then substitute on k= mv^2, but still wrong...

Last edited:

At a power of 435 hp, how much energy is produced in 6 seconds?

thats 2610 Hp or 1 947 060 Nm and substitute to energy... I ve tried that, and still got the wrong answer, my hunch is that we should utilize the given ( the 427 cu in engine) but tried it an still got the wrong answer... btw the answer on that one is 54 mph...

If you can show your full calculation, I might be able to spot what went wrong.

BTW, I am getting 53 m/s or 119 mph.

Redbelly98 said:
If you can show your full calculation, I might be able to spot what went wrong.

BTW, I am getting 53 m/s or 119 mph.

yeah I got it! Thank you very much!... I didn't know It was that easy, I wasted a week trying to solve this tricky problem...

## What is air resistance and why is it important to consider in scientific experiments?

Air resistance is the force that opposes the motion of an object through the air. It is important to consider in scientific experiments because it can significantly affect the accuracy of results, especially in experiments involving moving objects.

## How is air resistance calculated?

Air resistance is calculated using the formula F = 0.5 * ρ * v^2 * A * C, where F is the force of air resistance, ρ is the density of air, v is the velocity of the object, A is the cross-sectional area of the object, and C is the drag coefficient which depends on the shape and texture of the object.

## How does air resistance affect the motion of objects?

Air resistance can affect the motion of objects in several ways. It can decrease the speed of an object, increase the time it takes for an object to reach a certain distance, and change the direction of an object's motion. In some cases, air resistance can also cause an object to come to a stop.

## What factors can influence the force of air resistance?

The force of air resistance is influenced by several factors, including the speed and direction of the object, the density and viscosity of the air, the surface area and shape of the object, and the air pressure and temperature.

## How can the force of air resistance be reduced?

The force of air resistance can be reduced by changing the shape and texture of an object to make it more aerodynamic, increasing the speed of the object, decreasing the air pressure and temperature, and using materials with lower drag coefficients. In some cases, air resistance can also be reduced by using external forces, such as a propeller or engine, to counteract the resistance.

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