To Find Downward Force along Inclined Plane on a Roller Due to Gravitational Pul

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To Find Downward Force along Inclined Plane on a Roller due to Gravitational Pull of the Earth and Its Relationship with the Angle of Inclination


In this experiment, students need to determine the downward force along an inclined plane. The downward force is acting on a roller as a result of gravity. Gravity is a force that always pulls each object in a downward direction.

You can find the gravitational pull upon the object in this inclined plane experiment. The angle of inclination is denoted as θ. 

This is the angle that you need to determine and study its relationship with the gravitational pull. This is the article that can give you the liberty to verify and understand the truth.

Definition of Gravitational Pull

Gravitational pull is a downward force that attracts every object’s downwards to the centre of the earth. Higher mass objects have higher gravity. This is a universal force of attraction that is seen among all matters.

In this experiment, you will notice a force that is acting on a roller due to the gravitational pull of the earth.

Aim of the Experiment 

Students are here to find the downward force which is acting along an inclined plane. You can also determine the relationship between force and the angle of inclination (sin θ) with the help of graphs.

Some of the important apparatus or materials are mentioned below:

  • The inclined plane that comes with a protractor and a pulley

  • Weight box

  • Pan and thread

  • Roller

  • Spring balance

  • Spirit level

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Principle of the Experiment

In the above picture, students can notice a roller that has a mass of M1. This roller is kept over an inclined plane. The inclined plane has made an angle θ of with the horizontal.

It gives rise to an upward force that acts along the body over the inclined place. The body is always adjusting the suspended weights. 

One end of the string is linked to the mass via a pulley. This pulley is fixed and does not form the top of the plane. A farce is applied on the mass M1, and it helps the mass to move with a constant velocity ‘v’. 

An expression for the above is developed. It is represented as:

W = M1 g sin θ – fr

Here, W = Total tension in the string (Also, W = weight suspended)

M1 = mass of the roller

fr = force of friction because of rolling of the object

Experiment Procedure

  1. Prepare a plane with some angle of inclination. Then keep all necessary objects such as masses and a roller as per the given figure. Arrange all apparatus as shown in the diagram. 

  2. Arrange a pulley with the system of experiment and make it friction-proof. You can try to lubricate the pulley by using a machine whenever necessary.

  3. Students must focus on the adjustment of the suspended weight i.e., ‘W’. Make sure that the roller remains at the tip of the inclined during its rest condition.

  4. Now, start the decreasing of the mass gradually. You can do so by eliminating the mass out of the pan. You will notice that the roller is starting in a downward direction with a constant velocity. Now, it is time to note down the value of W and the angle θ.

  5. Let’s repeat step – 4 for two to three times for different values of θ and fill those details in a table for further observations.


Here, M1 g = Mass of the roller

M2 g = Mass of the pan

Students should write down up to three results for finding the appropriate output of the force.

S. No



Mass added to the pan M3


W = (M2 + M3)g N




Plotting Graph

After the result, a graph has been plotted between sin θ and force that shows a straight line.

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It is concluded that we can find the downward force with the help of the table along an inclined plane. Also, the graph shows that W is directly proportional to sin θ. Here, the angle of inclination is θ.

Mock Tests

1. What is the Relation Between the Angle of Inclination and the Downward Force in the above Experiment?

Ans: A relation that is developed between the angle of inclination and the downward is force is mg sin θ.

If you take the mass as constant, then W ∝ Sin θ.

2. How Do You Define an Inclined Plane?

Ans: An inclined plane can be made out of a wooden plane. When you place a glass sheet above the plane, it acts as an inclined plane. This has to be done to make the surface smooth. It has made an angle θ with the ground.

3. Write Down Some Applications of the Inclined Plane.

Ans: Here is the list of applications of the inclined planes:

  1. Ramps of your house

  2. The method is used in ladder

  3. A plank used at the back of the truck for lifting heavy goods

FAQ (Frequently Asked Questions)

Q1. Which One is the Natural Downward Force?

Ans: Gravity is called the natural downward force. It always acts downward to every object of the earth. This is the universal force that acts everywhere. When you throw an object into the air it will surely come back.

Q2. Calculate the Amount of Force Applied Over a Body that has a Mass of 15 kg and Travelling with an Acceleration of 3 m/s².

Ans: Data given, mass of the body = 15 kg

Acceleration of the body = 3 m/s²

So, the formula for the force is F = m * a = 15 * 3 = 45 Newton

Q3. Write Down Some Benefits of Friction.

Ans: Friction is a force that can co-exist when two bodies interact with each other. It helps us to generate multiple inventions in the past few days.

The following points are the benefits of friction:

  • Friction is very much important for other types of motion.

  • Brakes of cars are operated with the principle of friction

  • Asteroids get burnt while entering into the earth’s atmosphere due to friction.

  • Friction helps to generate heat energy.

  • We can walk upon the surface due to friction.