Simple machines questions | form two Physics

A lever which has its fulcrum between the effort and the load is said to be of:
A. first class
B. second class
C. third class
D. no class

Claw hammers and pairs of scissors are in which class of levers? ______________

A block and tackle containing 3 fixed and 2 movable pulleys is used to lift a load of 1200 N to a storey 15 m from the ground. if the work done in overcoming friction in the system is 6000 J. Calculate the
(i) Work done by the effort
(ii) Efficiency of the machine
(iii) Effort applied.

A lever which has its load between the effort and fulcrum is said to be:
A. First class lever.
B. Second class lever.
C. Third class lever.
D. None of the above.

The efficiency of a machine is ________

A system of levers with a velocity ratio of 40 overcomes a resistance of 3000 N when an effort of 100 N is applied. Its efficiency is:
A. 75%
B. 80%
C. 85%
D. 90%

Define the following:

1. Mechanical advantage
2. Velocity ratio
3. Efficiency of a machine

A simple machine was used to raise a load weighing 1000 N through a height of 5 m by applying an effort of 450 N. If the distance moved by the effort was found to be 25 m,
find:

1. Mechanical advantage
2. Velocity ratio
3. Efficiency of the machine

A machine has a velocity ratio of 15. If an effort of 10 N is applied to lift a load of 50 N, its efficiency is approximately equal to:
A. 20%
B. 33%
C. 50%
D. 75%

(a) Define the term “simple machine”.

(b) Write down the velocity ratio of the following simple machines:
(i) Inclined plane
(ii) A pulley system

(c) Why must a liquid and not a gas be used as fluid in a hydraulic machine?