diagram the motion of pistons in a four stroke engine.
You can find such diagrams by Googling "four stroke engine" or "Otto cycle" and asking for "images".
An example of what you will find is:
http://images.google.com/imgres?imgurl=http://www.antonine-education.co.uk/Physics_A2/options/Module_7/Topic_4/Otto.jpg&imgrefurl=http://www.antonine-education.co.uk/Physics_A2/options/Module_7/Topic_4/internal_combustion_engines.htm&usg=__-kJK_WVYwaIXSBfPllK1CJVzw_w=&h=380&w=576&sz=43&hl=en&start=4&tbnid=hEOqoJcSgs46PM:&tbnh=88&tbnw=134&prev=/images%3Fq%3D%2522otto%2Bcycle%2522%26gbv%3D2%26hl%3Den%26sa%3DG%26ie%3DUTF-8
A sample of compound AB decomposes to 48 g of A and 12 g of B. Another sample of the same compound AB decomposes to 24 g of A. Predict the number of grams of B obtained.
To diagram the motion of the pistons in a four-stroke engine, you will need to understand how each stroke of the engine cycle corresponds to the position of the pistons.
1. Intake Stroke: In this stroke, the piston moves downwards from the top (top dead center, TDC) position. This motion creates a vacuum in the cylinder, which allows the intake valve to open and the air-fuel mixture to be drawn into the combustion chamber.
2. Compression Stroke: After the intake stroke, the piston starts moving upwards (bottom dead center, BDC) to compress the air-fuel mixture in the combustion chamber. Both the intake and exhaust valves are closed during this stroke.
3. Power (Combustion) Stroke: At the top of the compression stroke (TDC), the spark plug ignites the compressed air-fuel mixture. This explosion pushes the piston downwards with force, creating power that is transferred to the crankshaft. The power stroke is the only stroke that generates energy.
4. Exhaust Stroke: As the power stroke ends, the piston moves upwards (BDC) to push out the burned gases from the combustion chamber through the exhaust valve. This stroke completes the engine cycle, preparing for the next intake stroke.
To summarize the piston motion in a four-stroke engine:
Intake Stroke: Piston moves downward (TDC to BDC)
Compression Stroke: Piston moves upward (BDC to TDC)
Power Stroke: Piston moves downward (TDC to BDC)
Exhaust Stroke: Piston moves upward (BDC to TDC)
It's important to note that in a multi-cylinder engine, the pistons of each cylinder are not always in the same stroke simultaneously. Each piston operates at a different point in the cycle, providing a smoother power delivery.