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2. Distinguish between:

a mechanical advantage and velocity ratio
b. velocity ratio and efficiency
c. second class lever and third class lever

3. Answer the following questions in short. a. Define lever. b. Which type of lever has effort in the middle? c. Which type of lever cannot change the direction of applied effort? d. Which lever cannot do work faster? e. Define mechanical advantage of a lever. f. Write a formula showing the relation of MA, VR and efficiency. g. What makes the value of efficiency always less than 100%?

4. Answer the following questions in detail. a. Introduce a lever. Also mention its types.​

1 Answer

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Answer:

Step-by-step explanation:

3. Short Answers:

a. A lever is a simple machine consisting of a rigid bar or rod that rotates around a fixed point called a fulcrum.

b. A second-class lever has the effort in the middle.

c. A first-class lever cannot change the direction of the applied effort.

d. A third-class lever cannot do work faster.

e. The mechanical advantage of a lever is the ratio of the output force to the input force.

f. The formula relating mechanical advantage (MA), velocity ratio (VR), and efficiency is: efficiency = (MA / VR) * 100.

g. The value of efficiency is always less than 100% because some energy is lost due to friction, heat, and other factors during the operation of the lever.

4. Detailed Answer:

A lever is a simple machine that helps amplify or redirect a force. It consists of a rigid beam or rod that is capable of rotating around a fixed point called a fulcrum. The fulcrum acts as a pivot point for the lever to move.

There are three types of levers: first-class, second-class, and third-class levers. In a first-class lever, the fulcrum is located between the effort and the load. Examples of first-class levers include a seesaw or a pair of scissors. This type of lever can change the direction of the applied effort.

In a second-class lever, the load is located between the fulcrum and the effort. An example of a second-class lever is a wheelbarrow. The effort is applied on one end, the load is at the other end, and the fulcrum is in the middle. Second-class levers provide a mechanical advantage, making it easier to lift heavy loads.

In a third-class lever, the effort is applied between the fulcrum and the load. Examples of third-class levers are tweezers or a baseball bat. Third-class levers do not provide a mechanical advantage, meaning that the effort force is greater than the load force. However, they allow for greater speed and range of motion.

The mechanical advantage of a lever is the ratio of the output force (load) to the input force (effort). It is a measure of how much the lever amplifies or reduces the force applied. A lever with a mechanical advantage greater than 1 amplifies the force, while a lever with a mechanical advantage less than 1 reduces the force required.

The formula relating mechanical advantage (MA), velocity ratio (VR), and efficiency is given by efficiency = (MA / VR) * 100. Efficiency represents the effectiveness of the lever in converting input force to output force. It is always less than 100% because some energy is lost due to factors like friction, heat, and other inefficiencies in the lever's operation.

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