Topic 9

Simple Machines

A screwdriver is used to pry the lid off a can of paint. What type of lever is the screwdriver in this instance?

1st Class

Leve

r

2nd Class Le

ver

3rd Class

Lever

It’s a

ctually

acting a

s an ...

0% 0%0%0%

1. 1st Class Lever2. 2nd Class Lever3. 3rd Class Lever4. It’s actually acting as an

inclined plane.

10

Calculate the ideal mechanical advantage of a ramp that is 25 meters long and rises a total of 3.0 meters.

.12 3.8.3 25 75

0% 0% 0%0%0%

1. .122. 3.03. 8.34. 255. 75

10

Calculate the ideal mechanical advantage of a machine with a wheel that has a radius of 35 cm and an axle with a radius of 10

cm.

.29 1.7 3.5 28350

0% 0% 0%0%0%

1. .292. 1.73. 3.54. 285. 350

10

Participant Scores12 Jacob12 Joey12 Daniel12 David12 Nicole B.

A single pulley is used to hoist a safe with a mass of 45.0 kg. If the machine is 100% efficient, what effort force will be required to

hoist the safe?

45.0 N

90.0 N 205 N

266 N 441 N

0% 0% 0%0%0%

1. 45.0 N2. 90.0 N3. 205 N4. 266 N5. 441 N

10

A snow shovel is an example of which type of lever? (Hint: The handle of the shovel is the fulcrum.)

1st Class

2nd Class

3rd Class

0% 0%0%

1. 1st Class2. 2nd Class3. 3rd Class

10

How long must an inclined plane be to push a 100 kg object to a height of 2.0 meters using a force of

200 N? Friction can be ignored.

2.0 m 9.8 m

50 m 100 m

200 m 400 m

0% 0% 0%0%0%0%

1. 2.0 m2. 9.8 m3. 50 m4. 100 m5. 200 m6. 400 m

10

A wheel and axle machine requires an effort force of 5.0 N to lift a load with a mass of 5.1 kg. If the machine is ideal and has a wheel radius of 12 cm, what is the radius of the axle?

1.0 cm 1.2 cm

5.0 cm 10 cm

1.2 m 2.4 m

0% 0% 0%0%0%0%

1. 1.0 cm2. 1.2 cm3. 5.0 cm4. 10 cm5. 1.2 m6. 2.4 m

10

Participant Scores28 Jacob28 Joey28 Daniel28 David28 Mackenzie

How much force would be required to lift a 200 kg object using a lever if the object is 0.500 meters from the fulcrum and the force

is applied 4.00 meters from the fulcrum?

20 N 25 N

196 N 245 N

1960 N

0% 0% 0%0%0%

1. 20 N2. 25 N3. 196 N4. 245 N5. 1960 N

Answer Now

10

What force will be required to push a 500 N box to a height of 2.50 meters on a ramp that is 10.0

meters long and 85% efficient?

4.00 N

50.0 N 106 125 N

147 N

0% 0% 0%0%0%

1. 4.00 N2. 50.0 N3. 106 4. 125 N5. 147 N

10

A pulley system is 85% efficient. If an effort force of 58.8 N is required to lift a 150 N load,

how many strings are pulling up in the system?

1 2 3 4 5

0% 0% 0%0%0%

1. 12. 23. 3 4. 45. 5

10

Calculate the ideal mechanical advantage of a lever in which the load is half the distance from the fulcrum as the effort force.

.5 1.1.5 2.

2.5

0% 0% 0%0%0%

1. 0.502. 1.003. 1.504. 2.005. 2.50

Answer Now

10

Participant Scores44 Jacob44 Mackenzie39 Nicole F.39 Joey39 Daniel

A ramp is 12 meters long and 3.0 meters high. It takes 145 N of force to push a 400 N crate up

the ramp. Determine the efficiency of the ramp.

0.36%0.69%

3.00%8.20%

36%69%

145%

0% 0% 0% 0%0%0%0%

1. .36 %2. .69 %3. 3.0 %4. 8.2 %5. 36 %6. 69 %7. 145 % 10

An object is placed 1.75 meters from the fulcrum of a lever. The effort force is 0.50

meters from the fulcrum. What is the actual mechanical advantage if the lever is 95%

efficient?

.271.286

.3013.33 3.5

3.68

0% 0% 0%0%0%0%

1. .2712. .2863. .3014. 3.335. 3.506. 3.68

Answer Now

10

A wheel and axle machine has a wheel radius of 15 cm and an axle radius of 6.5 cm. If an effort force of 49 N is required to lift a 10 kg object,

calculate the efficiency of the machine.

20%31%

69%80%

87%96%

0% 0% 0%0%0%0%

1. 20%2. 31%3. 69%4. 80%5. 87%6. 96%

Answer Now

10

Participant Scores56 Jacob56 Mackenzie51 Nicole F.51 Joey51 Daniel

A certain ramp is 10 meters long and is 50% efficient. It requires 25 N of force to push a 50 N

crate up the ramp. How tall is the ramp?

1.0 m 2.0 m

2.5 m 3.5 m

4.0 m 5.0 m

0% 0% 0%0%0%0%

1. 1.0 m2. 2.0 m3. 2.5 m4. 3.5 m5. 4.0 m6. 5.0 m

10

Which of the following are possibilities for the ideal mechanical advantage of a 2nd class lever?

(select all that apply)

less

than 1

equal to one

greater t

han one

0% 0%0%

1. less than 12. equal to one3. greater than one

10

Participant Scores0 Participant 10 Participant 20 Participant 30 Participant 40 Participant 50 Participant 60 Participant 70 Participant 80 Participant 90 Participant 10