Mechanical Advantage in Lever

Q.

What are the uses of joystick in points

Q.

A fire tongs has its arms 20 cm long. It is used to lift a coal of weight 1.5 kgf as shown in the figure below by applying an effort at distance 15 cm from the fulcrum. Find the mechanical advantage of fire tongs.

1. 75

2. 25

3. 0.75

4. 0.25

Q. Calculate the mechanical advantage of a lever in which the effort arm is 50 cm and the load arm is 2 cm ___.

1. 25
2. 100
3. 250
4. 10

Q. Why is the mechanical advantage of the lever of second order alway greater than one?

Q.

State the condition when a body is in dynamic equilibrium. Give one example of dynamic equilibrium.

Q.

A crowbar of length 2 m is used as a machine to lift a box of 100 kgf by placing a fulcrum at a distance of 0.1 m from the box. Calculate the effort required.?

Q.

Why is the cutting edge of the scissor made longer than the cutting edge of a mettal

Q.

When the effort arm is equal to the load arm the mechanical advantage is equal to one.

1. True

2. False

Q. A lever of length $9\text{cm}$ has its load arm $5\text{cm}$ long and the effort arm $9\text{cm}$ long:
(a) Which class does the lever belong to?
(b) What will be the mechanical advantage and velocity ratio if the efficiency becomes $50\%$?

Q.

When the effort arm is greater than the load arm then mechanical advantage is greater than one.

1. False

2. True

Q.

Write down a relation expressing the mechanical advantage of a lever.

Q.

State the condition when a body is in static equilibrium. Give one example of static equilibrium.

Q.

A fire tongs has its arms 20 cm long. It is used to lift a coal of weight 1.5 kgf by applying an effort at a distance of 15 cm from the fulcrum. Find : (i) the mechanical advantage of the fire tongs , and (ii) the effort needed.

Q.

A body in motion will remain in _______________ if balanced forces acts on it.

Q.

A crowbar of length 120 cm has its fulcrum situated at a distance of 20 cm from the load. Calculate the mechanical advantage of the crowbar.

Q. A pair of tongs has 20 cm long arms that can lift a piece of coal of weight 1.5 kgf, by applying an effort at distance 15 cm from the fulcrum. Calculate the mechanical advantage.

1. 0.75

Q. Calculate the effort arm (in cm) of a lever in which the mechanical advantage is $4$ and the load arm is $90\text{cm}$.

1. 360

Q.

The unequal and opposite forces acting on a body, which change its state of rest or uniform motion are called:

1. unbalanced forces

2. unlike parallel forces

3. like parallel forces

4. all of the above

Q. A pair of scissors has its blades 10 cm long, while its handles are 5 cm long. Find its mechanical advantage?

1. 0.5

Q.

Explain the following:

The stone of a hand flour grinder(chakki) is provided with a handle near its edge.

Q.

A body moves with constant speed of $5\frac{m}{s}$. This shows that balanced forces are acting on body

1. True
2. False

Q.

If balanced forces acts on body, body must be at rest

1. True
2. False

Q.

Give two reasons why the efficiency of a single movable pulley system is not $100\%$.

Q.

The given figure shows a uniform metre rule of weight W supported on a fulcrum at the 60 cm mark by applying the effort E at the 90 cm mark.

Find the mechanical advantage of the lever.

1. 3

2. 2

3. $\frac{2}{3}$

4. $\frac{1}{3}$

Q. A pair of scissors and a pair of pliers both belongs to the same class of levers. Name the class of lever. Which one has the mechanical advantage less than 1 ?

Q.

Explain the following :
A wrench or spanner has a long handle.

Q.

Calculate the mechanical advantage of a lever in which the effort arm is 50 cm and the load arm is 2cm ___.

Q.

A block and tackle system has 5 pulleys. If an effort of 1250 N is needed in the downward direction to raise a load of 5000 N calculate(a) M.A. (b) V.R.(c)efficiency of the system. Also find the magnitude of extra force needed to overcome the friction. In this question it is said that the extra force needed to overcome the friction. Now according to the answer it is 3750 Newton. If that is true then how will the efficiency amount to 100% because considering the extra force and the actual force the total effort would be 5000 Newton then the mechanical advantage would be 1 and the efficiency would amount to 20% only. Then how will the friction be overcomed?

Q.

An effort of 50 kgf is applied at the end of the lever of the second order, which supports a load of 750 kgf, such that the load is at a distance of 0.1 m from the hinge. Find the length of the lever.

[Assume lever is weightless]

Q. The mechanical advantage of a broom stick is always greater than 1

1. true
2. false