Radek Ocenas 8C
The Right Machine For The Job
Question: Which simple machine requires the least amount of force to lift a 1-kg mass?
Hypothesis: I think the easiest method that requires the least amount of effort will be the lifting with ramp.
Variables :
Manipulated variable - Distance E.F moved
Responding variable - different types of machines
Controlled variable - Mass
Material and equipment -
• 30cm string
• 1-kg mass
• 20-N spring scale
• ramp
• 60-cm string
• pulley system
• metre-stick
• 10-cm string
• pivot or fulcrum
Procedure:
Station 1. Lifting without a Machine
1. Tie a loop at one end of the 30-cm string, so the loop fits over the hook on the spring scale. Tie the other end of the string to the 1-kg mass.
2. Lift the spring scale just until the mass is hanging from the scale. Now slowly
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Measure and record the force needed to lift the mass.
Station 2. Lifting with a Ramp
3. Set up the ramp so that the highest point of the ramp is 10 cm above the top of the surface it’s sitting on.
4. Place the mass on the bottom of a ramp and attach the loop of string to the spring scale again. With your hand at the top of the ramp, pull the mass steadily up the ramp. Measure and record the force needed to raise the mass.
Station 3. Lifting with a Pulley System
5. Tie one end of the 60-cm string to the mass. Place the mass on a table below the pulleys and thread the string between the pulleys.
6. Tie a loop at the loose end of the string and attach the string to the spring scale. Use the pulleys to raise the load 10 cm. Measure and record the force needed to lift the mass
Lifting Method
Without Machine
Lifting with ramp
1st class lever
2nd class lever
3rd class
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