The Simple Pulley

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.

1. 0.5 m

2. 0.2 m

3. 0.1 m

4. 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 ___ it.

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. 1

2. 2

3. 3

4. 0

Q.

One joule work is said to be done when:

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

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

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

4. 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 $B$?

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

2. $\frac{5g}{2}$

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

4. $\frac{2g}{5}$

Q. Why pulling is easier than pushing a body

Q. In a single fixed pulley, the velocity ratio is alwaysthe mechanical advantage.

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

Q.

Single fixed pulley can be used as a force multiplier.

1. True

2. 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. 1.2

2. 1.6

3. 2.0

4. 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 is used to change the direction of force.

1. screw
2. wedge
3. 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.

1. 83.3%

2. 86.6%

3. 72.5%

4. 75%

Q.

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

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

2. When a horse pulls a cart on a level road.

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

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