Class 1 Lever When MA<1

Q.

A pair of scissors has its blades 15 cm long, while its handles are 7.5 cm long. What is its mechanical advantage ?

Q.

In Fig 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.

(a) State with reason whether the weight W of the rule is greater than, less than or equal to the effort E.

(b) Find the mechanical advantage in an ideal case.

Q.

A football player kicks a football to another player of his team who kicks it towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team.

The momentum of football changes:

1. two times

2. three times

3. one time

4. four times

Q.

In a pair of scissors, the blade is longer than the blades of a shear which is used for cutting the metal sheet. Explain the reason.

Q.

What is the mechanical advantage of a hammer used for driving a nail?

Q.

A pair of scissors is used to cut a piece of a cloth by keeping it at a distance of 8.0 cm from its rivet and applying an effort of 10 kgf by fingers at a distance of 2.0 cm from the rivet.

(a) Find : (i) the mechanical advantage of scissors, and (ii) the load offered by the cloth.

(b) How does the pair of scissors act : as a force multiplier or as a speed multiplier ?

Q.

SHOW HOW A SINGLE PULLEY CAN BE USED TO REDUCE THE EFFORT REQUIRED TO OVERCOME A GIVEN LOAD . DRAW A DIAGRAM OF THE SYSTEM . WHY IS IT GENERALLY MORE CONVENIENT TO USE TWO PULLEYS FORTHIS ? ANME TWO PULLEYS

Q. State the kind of lever which always has the mechanical advantage less than 1. Draw a labelled diagram of such lever.

Q.

what is meant by fulcrum, lever, piote(verb)

Q. A uniform rod of length 6meter is pivoted at a point of 1/3 of its end from one end . Another person hold this rod by applying minimum weight of 100gf . Calculate the weight of the rod?

Q.

Give reason:

There is not much difference in the length of the handle and blades in ordinary scissors used for cutting paper or cloth.

Q. A car weighing 1000 kg collides with a stationary 50 kg trolley, and imparts a velocity of $75m{s}^{-1}$ to it. Find the speed with which the car was moving (Assume that the car comes to a stop after the collision and neglect friction at the time of collision).

1. $4.75m{s}^{-1}$
2. $3.5m{s}^{-1}$
3. $3.25m{s}^{-1}$
4. $4.25m{s}^{-1}$

Q. A pair of scissors has its blades 15 cm long, while its handles are 8 cm long, the M.A. =

1. 1.875
2. 3.75
3. 0.533
4. 1.067

Q. With the help of a car jack, a person lifts a $1.2$ tonne car. If the jack’s MA is $8$, how many times has the person’s effort been reduced by in lifting the car compared to when there is no jack? (Take $g$= $10{\text{m s}}^{–2}$)

1. $8$
2. $80$
3. $12.5$
4. $1.25$

Q. A body of mass $300\text{g}$ kept at rest breaks into two parts due to internal forces. One part of mass $200\text{g}$ is found to move at a velocity of $12{\text{m s}}^{-1}$ towards east. The velocity of the other part is:

1. $24{\text{m s}}^{-1}$ towards west
2. $24{\text{m s}}^{-1}$ towards east
3. $14{\text{m s}}^{-1}$ towards east
4. $54{\text{m s}}^{-1}$ towards south

Q.

Explain why scissors for cutting cloth may have blades longer than the handles, but shears for cutting metals have short blades and long handles.

Q.

What is the use of the lever, if its mechanical advantage is less than 1?

1. As a force multiplier

2. To obtain the gain in speed

3. To change the direction of force

4. As a work multipler