HARD

Earn 100

A block and tackle system of pulleys consists of $8$ pulleys. A load of $1000 kgf$ is lifted by an effort of $250 kgf$ , efficiency is :

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Important Questions on Machines

HARD

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

Draw a diagram to show a block and tackle pulley system having a velocity ratio of $3$ marking the direction of load (L), effort (E) and tension (T).

The pulley system drawn lifts a load of $150 N$ when an effort of $60 N$ is applied. Find its mechanical advantage. Is the above pulley system an ideal machine or not?

EASY

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

A woman draws water from a well using a fixed pulley. The mass of bucket and water together is

6 kg

. The force applied by the woman is

70 N

. Calculate the mechanical advantage. (Take

g = 10 m s^{- 2}

EASY

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

Mechanical advantage of a machine defined as

HARD

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

An effort of

500 N

is applied through a distance of

0.50 m

on a machine, whose efficiency is

90 %

such that resistance is overcome through a distance of

0.04 m

. Calculate: -

(i)

velocity ratio,

(ii)

mechanical advantage,

(iii)

resistance overcome by the machine.

MEDIUM

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

Draw a diagram of a block and tackle system of pulleys having a V.R. of $5$ . In your diagram, indicate clearly the points of application of load and effort.

MEDIUM

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

Figure below shows a wheelbarrow of mass

15 kg

carrying a load of

30 kgf

with its centre of gravity at

A

. The points

B

and

C

are the centre of wheel and tip of the handle such that the horizontal distance

A B = 20 cm

and

A C = 40 cm

Calculate: (i) the load arm, (ii) the effort arm, (iii) the mechanical advantage and (iv) the minimum effort required to keep the leg just off the ground.

EASY

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

Mechanical advantage of an inclined plane is always _____.( greater than one, less than one)

EASY

Science>Physics>Machines>Relation between Efficiency, Mechanical Advantage and Velocity Ratio

A crowbar of length