These pages are designed to help students prepare for the tests, quizzes, and other assignments throughout the duration of the course.

 

Parents


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Practice Problems

 

Find the type of practice problem that you need.
There are Concept Questions, as well as Math Practice Problems.
You can put in any value you want or have it put in a set of numbers for you.
Pop-up Blockers will need to be turned off for these to work!!

Work Power and Simple Machines

Multiple Choice

Answer all the Multiple Choice Questions then hit "Check" after the last multiple choice question

Which of the following is not considered work?
pushing a book across the desk
lifting a pencil off of the floor
Pushing a crate 6 meters up an inclined plane
carrying your bookbag across the room

Using the scientific definition, which of the following is true of work?
it must be difficult
it must involve levers
it must involve the transfer of energy
it must be done with a machine

Carrying a bookbag can be considered work, if...
the weight of the bookbag is more than 25 N
the bookbag is carried for more than 30 seconds
if you carry it up a flight of stairs
it is a blue bookbag

If you increase the power of the machine, it will _____?
take longer to do the same amount of work
do less work
take less time to do the same amount of work
none of the above

A device that is used to make work easier is called ______.
effort force
machine
efficiency
mechanical advantage

Which of the following statements are true about the term "Efficiency"?
No machine can be 100% efficent.
Friction in a machine reduces efficiency
Efficiency is found by dividing work output by work input x 100%
all of the above

The higher the Mechanical advantage, the _________.
the more simple machines that are needed
the easier it is to do the work
the lower the effort force needed to do the work
b and c

A fixed pulley can
only change the direction of the effort force
increase the effort force
have a mechanical advantage of 2 or more
reduce the resistance force

How much work do you do when you lift a 1.5 kg can of paint to a height of 10 m?
150 J
147 N
15 N
15 J

When a machine does work on an object, the output work is
always less than the input work
always equal to the input work
always greater than the input work
sometimes equal to the input work
not enough information

Which of the following can a machine do?
increase the amount of work done
increase the distance over which the effort force is exerted
multiply the effort force
change the direction the force is being applied
A and B
B and C
A, B, C
B, C, D

What is the ideal mechanical advantage of an inclined plane that is 6.0 m long and 1.5 m high?
4
0.2
1.5
4.2

If the radius of a doorknob is 6.0 cm and the radius of its inner rod is 2 cm, what is the mechanical advantage?
8
6
4
3

What is the mechanical advantage of a lever that is requires a person to exert a force of 50 N in order for the lever to lift a box with a force of 250 N?
300
0.2
5
200

In which of the following situations do your arms do work on a bookbag?
carrying the bookbag through the hall
holding a bookbag while standing in one place
lifting the bookbag off the floor
none of the above are work
all of the above are work

Which of the following describes a first-class lever?
resistance force located between the effort force and fulcrum
effort force located between the resistance force and fulcrum
fulcrum located between the effort and resistance forces
effort force and resistance force in same location

Which of the following describes a second-class lever?
resistance force located between the effort force and fulcrum
effort force located between the resistance force and fulcrum
fulcrum located between the effort and resistance forces
effort force and resistance force in same location

A fixed pulley always has an ideal mechanical advantage of:
0
1
2
5

A simple machine has an efficiency of 60%. What will be the machine's work output if the work input is 5000 J
8333 J
3000 J
83.33 J
30 J

The efficiency of a certain lever is 75%. If a person uses a force of 1000 N to push the lever down 1.5 m, then how far does the 1200 N resistance force move?
1125 m
1.3 m
0.94 m
5 m

What is the efficiency if the work put into a machine is 7500 Joules, but the machine only does 3200 Joules of work?
0.43 %
2.34 %
234 %
43 %

A 3rd class lever has a effort arm of 1.2 m and a resistance arm of 3.6 m. What is the lever's mechanical advantage?
0.33
3
4.32
10

A pulley that has a mechanical advantage of 8 is used to lift a 6500 N object. How much force does it take to lift the object?
300
812.5 N
52000
520

Fill in the Blank and True/False

Best used with lowercase letters only
1. is the unit for measuring force?

2. is the unit for measuring power?

3. is the unit for measuring work?

4. A rope that is pulled over a grooved wheel is called a ?

5. A bar that is free to pivot around a fixed point is called a ?

6. A pencil sharpener is an everyday example of which simple machine?

7. A spiral staircase best exemplifies which simple machine?

7.
This drill bit best describes which simple machine?

8. Most objects that are sharp and that are used for cutting or slicing would best describe which simple machine?

9. True or False: A high mechanical advantage means that it is harder to do the work.

Which Class of Lever?

Type in 1 for first class, 2 for 2nd, and 3 for 3rd class levers.
1.
which class of lever is this?

2.
which class of lever is this?

3.
which class of lever is this?

4.
which class of lever is this?

5.
which class of lever is this?

6.
which class of lever is this?

7.
which class of lever is this?

8.
which class of lever is this?

Ch. 5 Math Problems

Math Problems


1. How much work does a boy do when he is pushing a box with N, if he pushes it meters?


2. A snowplow does J of work when it pushes snow off the street. If the snowplow moves the snow meters, then what force was the snowplow pushing with?


3. A robot pushes a shopping cart with a force of N, as it pushes the cart across the store. If the robot does Joules of work in pushing the cart, then how far was the cart pushed by the robot?


4. How much power does a motorized toy car have if it does Joules of work in seconds?


5. It took minutes to move a refrigerator. If you did Joules of work in the process, how much power was required to move the refrigerator?


6. A person did Joules of work in pushing a bowling ball, if the person's power was watts, then how much time was the person pushing the bowling ball?


7. A pulley was used to pick a crate up to the top of a building. If the total power used was Watts, then how much work was done if it required seconds to lift the crate to the top?






Physical Science