25 Questions
What is the primary function of a linkage?
To transfer energy from an energy source to an object
Which of the following is a special type of linkage used in large vehicles?
Transmission
What is the primary characteristic of gears when they are meshed together?
They alternate the direction of spin
Which of the following statements about gears is true?
Gears can change the speed, force, and direction of motion
What is the term used for gears that integrate with a linkage, such as gears on a bicycle?
Sprocket
What is a key feature of a first-class lever?
Fulcrum is between the load and the effort
How does an inclined plane help the user move a larger load?
By increasing the distance over which the load is moved
What distinguishes a wedge from an inclined plane?
Splits an object by pressing on the narrow end
In a second-class lever, where is the load positioned?
Between the fulcrum and the effort
Which type of lever requires the user to move a greater distance than the load?
Third class lever
If the number of teeth on the driven gear is 40 and the number of teeth on the driver gear is 20, what is the mechanical advantage?
$MA = 2$
If the mechanical advantage of a machine is less than 1, what is true about the input force required?
A greater input force is required to overcome the output force.
What is the relationship between the mechanical advantage and the distance the input force travels?
If the mechanical advantage is greater than 1, the input distance is greater than the output distance.
If a ramp has a greater mechanical advantage, what can be inferred about the ramp?
The ramp is less steep.
What is the speed ratio used to measure?
How the speed of an object is affected by a machine
What is the purpose of an inclined plane?
To lift heavy objects using a smaller force over a longer distance
What is the relationship between the number of teeth on the driver gear and the driven gear, and the mechanical advantage (MA)?
MA is equal to the number of teeth on the driven gear divided by the number of teeth on the driver gear
If the speed ratio (SR) of a machine is 0.5, what does this indicate?
The user is moving half as fast as the load
How does friction affect the mechanical advantage of a machine?
Friction decreases the mechanical advantage of a machine
What is a way to reduce the effects of friction on mechanical advantage?
Lubricate the machine's moving parts to reduce friction
What is the mechanical advantage of using a wheelbarrow for Justin to move the load of bricks?
2.5
How is the mechanical advantage of a pulley system calculated?
By counting the number of pulleys within the system
In the context of calculating mechanical advantage for screws, what does 'l' represent in the formula MA = πdm l?
Pitch of the screw
For a screw with a radius of 9mm and a pitch of 3mm, what is its mechanical advantage?
14
How does length and height affect the mechanical advantage of an inclined plane?
Length increases, MA increases; Height increases, MA decreases.
Study Notes
Mechanical Advantage (MA)
- MA increases when length remains constant and height decreases
- To increase MA, increase length or decrease height
- MA is calculated as output force (load) divided by input force (force you apply) or input arm distance divided by output arm distance
Calculating Mechanical Advantage (Gears/Gear Trains)
- MA is calculated as the gear ratio (GR), where GR is the number of teeth on the driven gear divided by the number of teeth on the driver gear
- Example: MA = 30 teeth / 20 teeth = 1.5
Inclined Planes
- An inclined plane makes it possible to lift heavy objects using a smaller force, but the object must be moved over a longer distance
- MA is calculated as the length of the slope divided by the height of the slope
Speed Ratio (SR)
- SR measures how the speed of an object is affected by a machine
- SR is calculated as the number of teeth on the driven gear divided by the number of teeth on the driver gear
Effects of Friction on MA
- Friction can reduce the efficiency of a machine and decrease MA
- Lubricating machine parts can reduce friction and increase MA
Types of Levers
- First-class lever: fulcrum between the load and the point of effort
- Second-class lever: load is between the effort and the fulcrum
- Third-class lever: effort is between the load and the fulcrum
Inclined Planes and Wedges
- Inclined planes enable users to move larger loads, but require a longer distance to be moved
- Wedges are similar to inclined planes, but are forced into an object and can only be used in one direction
Subsystems that Transfer Forces
- Linkage: a belt or chain to transfer energy from a source to an object
- Transmission: a special type of linkage for transferring energy from the engine to the wheel in large vehicles
Gears
- Four characteristics of gears:
- Gear wheels work together in gear trains
- Gears can change the speed, force, and direction of motion
- Gears will alternate the direction of spin
- Gears integrate with other gears and can integrate with linkages
Learn about levers, a rigid bar that can rotate around a fixed point called a pivot or fulcrum. Discover how different types of levers - first class, second class, and third class - are used to move loads by exerting effort at different points.
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