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Simple Machines and Power. Exam
Questions And Answers (Guaranteed A+)
The diagram below shows the relationship among the amount of energy that is added to a
mechanical system (Ein), the amount of useful energy that is produced by the system (Eout),
and the amount of heat generated during the mechanical process. - answer✔*The amount of
useful energy that is produced is less than the amount of energy that was initially added to the
system.
*The system obeys the law of conservation of energy.
The _______ of a machine is the amount by which a machine multiplies the force applied to it
when accounting for energy lost due to friction. - answer✔actual mechanical advantage
Rick is moving a wheelbarrow full of bricks out to the curb. The bricks in the wheelbarrow
weigh more than Rick is able to carry, yet he is able to move the bricks. How is this possible? -
answer✔When Rick lifts the handles of the wheelbarrow most of the weight of the
wheelbarrow's load goes onto its wheel.
Tracy pushes a block up an inclined plane to a height of 1.0 m. If Tracy puts 505 J of work into
the system, but only 444 J are used to elevate the block, what is the efficiency of the inclined
plane? - answer✔88%
What does a pulley system need in order to reduce the force needed to lift an object? -
answer✔at least one movable pulley
Greg is moving a pile of dirt across his yard using a wheelbarrow. The main simple machines
that make up the wheelbarrow are: - answer✔a lever and a wheel and axle.
A crowbar is an example of what type of simple machine? - answer✔lever
Newton's cradle is a science toy that is often used to demonstrate the law of conservation of
energy.When one ball is raised, it acquires potential energy which is then transformed into
kinetic energy once the ball is released.In theory, the total energy should be conserved such
that the balls continue in perpetual motion. However, over time, the balls stop moving. Why? -
answer✔Some of the energy is converted into heat.
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