Mechanical Advantage

Q. State Newton's first law of motion. Why it is called law of inetria?

Q. What do you understand by the term couple? State its effect. Give two examples of couple action in our daily life.

Q.

When does a machine act as (a) a force multiplier, (b) a speed multiplier? Can a machine act as a force multiplier and a speed multiplier simultaneously?

Q.

Name the factors affecting the turning effect of a body.

Q.

Define mechanical advantage of a machine. Why it has no unit?

Q.

A Force of 50 dynes acts on a rigid body, such that the perpendicular distance between the fulcrum and the point of application of force is 75 cm. calculate the moment of force?

Q.

What is the other name for Newtons first law of motion?

Q.

Calculate the force which will produce a moment of force of 1575 dyne-cm, when the perpendicular distance between the point of application of force and the turning point is 45 cm

Q. If the effort applied is greater than the load, then the mechanical advantage is .

1. greater than 1
2. less than 1
3. equal to zero

Q.

Explain the term mechanical advantage. State its unit.

Q.

How is the mechanical advantage (MA) related to the velocity ratio (VR) for an ideal machine?

1. M.A = V.R

2. M.A > V.R

3. M.A < V.R

4. M.A = 2 x V.R

Q. Figure shows a block and tackle system of pulleys used to lift a load. How many strands of tackle are supporting the load?

Q.
A fixed and movable pulley system has 50% efficiency. Find the velocity ratio of the system.

[1 mark]

1. $2^2$
2. $2^3$
3. $3^2$
4. $3^3$

Q.

Calculate the Mechanical Advantage(M.A) for a load of 40 N, when the required force to lift the load is 15 N.

1. 2.7

2. 2.07

3. 0.7

4. 1.7

Q. A block and tackle system has the velocity ratio 3. Draw a labelled diagram of the system indicating the points of application and the directions of load L and effort E. A man can exert a pull of $200kgf$. What is the maximum load he can raise with this pulley system if its efficiency is 60%?

Q. Water sprinkler used for grass lawns begins to rotate as soon as the water is supplied. Explain the principle on which it works.

Q.

Calculate the mechanical advantage of a lever whose input arm is 80 cm long and the output arm is 5 cm long.

1. 14

2. 16

3. 18

4. 20

Q. In a block and tackle system consisting of 3 pulleys, a load of $75kgf$ is raised with an effort of $25kgf$, find the velocity ratio.

Q. Figure shows a block and tackle system of pulleys used to lift a load. Draw arrows to represent tension T in each strand.

Q.

What is an ideal machine?

Q.

Which of the following is the condition for force multiplier?

1. Effort needed is less than the load.

2. Effort needed is equal to the load.

3. Effort needed is equal to zero

4. Effort needed is more than the load.

Q. State Newton's first law of motion. Why it is called law of inetria?

Q. In figure, draw a tackle to lift the load by applying the force in the downward direction. If the load is raised by 1 m, through what distance will the effort move?

Q.

What happens if a force is applied to a body which is not free to move but pivoted to a point?

Q. For a machine of efficiency 100%, mechanical advantage:

[1 mark]

1. is greater than the velocity ratio
2. is equal to the velocity ratio
3. is less than the velocity ratio
4. does not depend on the velocity ratio

Q. Figure shows a system of four pulleys. The upper two pulleys are fixed and the lower two are movable. (a) How are load and effort of the pulley system related? (b) What assumption do you make in arriving at your answer in part (a)?

Q. A block and tackle system has 5 pulleys. If an effort of $1000N$ is needed in the downward direction to raise a load of $4500N$, calculate the mechanical advantage.

Q. Figure shows a block and tackle system of pulleys used to lift a load. When load is pulled up by a distance 1 m, how far does the effort end move?

Q. A tong has its arms 20 cm long. It is used to lift coal of weight 1.5 kgf by applying an effort at distance 15 cm from the fulcrum. The mechanical advantage is.

1. 75
2. 25
3. 0.25
4. 0.75

Q. A block and tackle system has the velocity ratio 3. Draw a labelled diagram of the system indicating the points of application and the directions of load L and effort E. A man can exert a pull of 200 kgf. If the effort end moves a distance 60 cm, what distance does the load move?