Work and Mechanical Advantage

How much work is produced when 350 N is used to move a car 5 m?

• 70 J
• 1750 J
• 355 J
• 175 J

Lamar Gant, U.S. powerlifting star, became the first man to deadlift five times his own body weight in 1985. Deadlifting involves raising a loaded barbell from the floor to a position above the head with outstretched arms. Determine the work done by Lamar in deadlifting 300 kg to a height of 0.90 m above the ground.

• 270 J
• 2646 J
• 333 J
• 3.00X10^-3 J

What is a machine?

• an object that works for guilty pleasures
• an object that is designed to take over the earth in 2020
• simplest mechanisms that use mechanical advantage to multiply force.
• a mechanism that is used to decrease the amount of work done

What is mechanical advantage?

• The advantage a machine has over a bicycle
• A measure of how much a simple machine reduces work
• A measure of when is the best time to use a simple machine
• A measure of the force amplification achieved by using a tool

What is effort (input) force?

• the force required by a machine in order to accomplish work (the force you put on the machine)
• the force which an effort force must overcome in order to do work on an object via a simple machine.
• the force the machine exerts on a object
• the output work times the input distance

What is resistance (output) force?

• the force required by a machine in order to accomplish work (the force you put on the machine)
• the force which an effort force must overcome in order to do work on an object via a simple machine.
• the force the machine exerts on a object
• the output work times the input distance

What is effort (input) distance?

• the force required by a machine in order to accomplish work (the force you put on the machine)
• the force which an effort force must overcome in order to do work on an object via a simple machine.
• the distance an input force moves a machine
• the output work times the input distance

What is resistance (output) distance?

• the force required by a machine in order to accomplish work (the force you put on the machine)
• the force which an effort force must overcome in order to do work on an object via a simple machine.
• the distance an input force moves a machine
• the distance through which the output force is exerted

How can you determine the mechanical advantage of a pulley system?

• Count the number of rope/cable segments on each side of the pulleys, including the free end. If the free end is to be pulled down, subtract 1 from this number.
• Count the number of rope/cable segments on each side of the pulleys without including the free end.
• Count the number of rope/cable segments on the central pulleys.
• Count the number of rope/cable segments on each side of the pulleys, including the free end. If the free end is to be pulled down, subtract 10 from this number.

What is the mechanical advantage of this pulley system?

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• 5