# Solve for Length of Stroke for Air Entering Tyre

• spirally
In summary, the question asks for the length of stroke needed to enter air into a tire against a pressure of 4 bar, assuming a stroke of 20cm and atmospheric pressure of 1 bar. It is mentioned that the pressure and stroke are inversely related and that the rate of compression affects the temperature of the compressed air. Without additional information, the exact values cannot be calculated.
spirally
an urgent help needed

A bicycle pump which has a stroke of 20cm is used to force air into a tyre against a pressure
of 4bar.what length of stroke will be swept through before air begins to enter the tyre when the piston is pushed (a)slowly (b)quickly. Assume atmospheric pressure to be 1 bar

pls help

i have practically no idea at all that is why i came to the forum for assistance.
how can i show what i have done when i have no ideas at all?

Air (or any fluid) flows from high pressure to low pressure. When does the pressure in the bore of the pump just equal to the pressure in the tire?

remember - every great scientist had humble beginings

spirally said:
i have practically no idea at all that is why i came to the forum for assistance.
how can i show what i have done when i have no ideas at all?

Sorry I can't help you, I can't remeber anything on this subject.

But a word of advice: If you don't know how to do it (no idea) say so, or you'll always get this reply.

spirally said:
A bicycle pump which has a stroke of 20cm is used to force air into a tyre against a pressure
of 4bar.what length of stroke will be swept through before air begins to enter the tyre when the piston is pushed (a)slowly (b)quickly. Assume atmospheric pressure to be 1 bar

In the case of gasses volume and pressure are inversely related. Meaning at 50% stroke ie. 10 cm the cylinder pressure will attain 2 bar, at 75% stroke it will be 4 bar, @ 15 cm. Rate has nothing to do with pressure, but will have an effect on the temerature of the compressed air, higher rate of compression means less time to cool off to ambient. Pressures vs stroke are assuming the temperature has returned to the same temp as the initial. Exact values for dynamic points must also include the energy input required to compress the air and are 0 Kelvin referenced. 4 Bar in your problem will in a real airpump be attained before the 15 cm mark due to compression heating of the air, but without cylinder area and ambient temp. of the uncompressed air heat transfer rates cannot be calculated.

## 1. What is the length of stroke for air entering a tyre?

The length of stroke for air entering a tyre refers to the distance that the piston or plunger must travel in order to allow air to enter the tyre. This distance can vary depending on the type of tyre and the amount of air needed to fill it.

## 2. How is the length of stroke for air entering a tyre determined?

The length of stroke for air entering a tyre is determined by the volume of air needed to fill the tyre and the displacement of the piston or plunger. This can be calculated using the ideal gas law and the dimensions of the tyre and air chamber.

## 3. Why is the length of stroke for air entering a tyre important?

The length of stroke for air entering a tyre is important because it directly affects the amount of air that can be pumped into the tyre. If the length of stroke is too short, the tyre may not be properly inflated, while a stroke that is too long may result in over-inflation and potential damage to the tyre.

## 4. Are there different methods for measuring the length of stroke for air entering a tyre?

Yes, there are different methods for measuring the length of stroke for air entering a tyre, including using a ruler or caliper to physically measure the displacement of the piston or plunger, or using mathematical calculations based on the dimensions and volume of the tyre and air chamber.

## 5. How can the length of stroke for air entering a tyre be adjusted?

The length of stroke for air entering a tyre can be adjusted by changing the displacement of the piston or plunger, or by altering the dimensions of the tyre or air chamber. This can be done manually or through the use of specialized equipment and tools.

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