# The Simple Pulley

## Trending Questions

**Q.**

Define work done by a force and give some examples of it

**Q.**

Define 1 J of work.

**Q.**

A mass of $0.5kg$ moving with a speed of $1.5\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$ on a horizontal smooth surface collides with a nearly weightless spring of force constant, $k=50N/m$. The maximum compression of the spring would be

**Q.**

Give some practical examples of an application of couple.

**Q.**

Calculate the height through which a body of mass 0.5 kg should be lifted if the energy spent for doing so is 1.0 joule.

0.5 m

0.2 m

0.1 m

2.0 m

**Q.**

What is a fixed pulley?

**Q.**

What is the velocity ratio of a single fixed pulley?

**Q.**

A pulley system has a velocity ratio $5$. Draw a neat labeled diagram of the pulley system to lift a load by applying the effort in a convenient direction. Mark the tension in your diagram.

(i) If the efficiency of the system is $80\%$, find its mechanical advantage.

(ii) If a load of $10\mathrm{kgf}$ is pulled up by a distance of $2\mathrm{m}$ in $10\mathrm{s}$, calculate the power developed by the effort.

**Q.**

Question 3 (c)

Fill in the blanks in the following statements:

(c) To move a loaded trolley we have to

**Q.**

Calculate the height through which a body of mass 0.5 kg should be lifted if the energy spent for doing so is 1 joule take g=10 m/second square

**Q.**Two cars get closer by 8 m every second while travelling in opposite directions. They get closer by 0.8m while travelling in same direction . wht are speeds of two car ?

**Q.**

Name the pulley which has no gain in mechanical advantage. Explain, why is such a pulley then used ?

**Q.**

The mechanical advantage of a single fixed Pulley is

1

2

3

0

**Q.**

One joule work is said to be done when:

A force of 1 N displaces a body by 1 cm.

A force of 1 N displaces a body by 1 m.

A force of 1 dyne displaces a body by 1 cm.

A force of 1 dyne displaces a body by 1 m.

**Q.**

Give one example of a machine for the use of changing the direction of force.

**Q.**

When we apply a force parallel to the door, it does not rotate about the hinge. Justify this statement.

**Q.**

What are the SI and CGS units of work?

**Q.**

In the figure shown neglecting friction and mass of pulleys, what is the acceleration of mass $B$?

$\frac{g}{3}$

$\frac{5g}{2}$

$\frac{2g}{2}$

$\frac{2g}{5}$

**Q.**Why pulling is easier than pushing a body

**Q.**In a single fixed pulley, the velocity ratio is always

- equal to
- less than
- greater than or equal to

**Q.**

Single fixed pulley can be used as a force multiplier.

True

False

**Q.**

Define the term pulley. What for single fixed pulley is commonly used.

**Q.**Which is more stable .Mn2+ or Cr3+

**Q.**

A single fixed pulley is used because it :

(a) ha sthe mechanical advantage greater than 1

(b) has the velocity ratio less than 1

(c) gives 100% efficiency

(d) helps to apply the effort in a convenient direction.

**Q.**

In a single fixed pulley, if the effort moves by a distance x downwards, by what height is the load raised upwards ?

**Q.**

A pulley system has a velocity ratio 3 and an efficiency of 80%. Calculate the mechanical advantage of the system.

1.2

1.6

2.0

2.4

**Q.**

Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?

**Q.**A

- screw
- wedge
- pulley

**Q.**

A boy lifts a load of 400 N through a vertical height of 5 m by a fixed pulley by applying an effort of 480 N at the other end.

Find the efficiency.

83.3%

86.6%

72.5%

75%

**Q.**

Which of the following is not a zero-effort situation?

The work done by the tension in the string, when a body tied with the string move along a circular path.

When a horse pulls a cart on a level road.

The work is done by a coolie when he travels on a horizontal platform, with a load on his head.

When a person holds some amount of load but, does not move from his position.