ICSE.X.PHYSICS. 3. MACHINES

Efficiency of a machine is:

• output / input

• output × input

• input / output

• output + input

For a Class I lever:

• VR = 1

• VR > 1

• VR < 1

• any of these

For a Class II lever:

• VR = 1

• VR > 1

• VR < 1

• none of these

For a Class III lever:

• VR = 1

• VR > 1

• VR < 1

• none of these

Which of the following is not a function of a machine?

• To act as a force multiplier

• To change the direction of the effort applied for greater ease and comfort

• To shift the point of application to a convenient place

• To decrease speed.

If a machine is an ideal machine, then the ratio of mechanical advantage (MA) to the velocity ratio (VR) is:

• equal to one

• less than one

• greater than 1

• can have any value.

Which of the following is not true for a machine?

• MA can be less than one

• MA can be greater than VR

• It can multiply speed

• It always has an efficiency less than 100%.

The class of lever, which acts as a force multiplier is:

• class one

• class two

• class three

• none of these

The mechanical advantage of a machine is 4 and its velocity ratio is 5. The efficiency of the machine is:

• 70%

• 80%

• 60%

• 90%

Mechanical advantage (MA), load (L) and effort (E) are related as:

• MA × E = L

• MA = L × E

• E = MA × L

• none of these