Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Acceleration on an Inclined Plane Explained

Reviewed by:
ffImage
hightlight icon
highlight icon
highlight icon
share icon
copy icon
SearchIcon
widget title icon
Latest Updates

How to Calculate Acceleration on Inclined Surfaces in Physics

It is also called a ramp. The plane which is inclined is one of the six simple machines. Objects which are placed on an inclined plane accelerate due to a force which is unbalanced. In this article we will analyze the motion experienced by an object placed on a plain which is inclined.


Normal Force 

The force which is a normal force in an inclined plane is not directed in the direction that we are accustomed to. We have up till now always seen normal force directed upwards in the direction which is opposite to the force of gravity. 

[Image will be uploaded soon]


Gravity Force

To find out the net force which is acting upon an object on an inclined plane is difficult because the two forces that are already acting on the body are not opposite in directions. To simplify this whole thing one of the forces acting on the object will have to be resolved into direction which is perpendicular components so that they can be added to other forces. The force that is directed at an angle to the horizontal of the plane is resolved into vertical and horizontal components. In the case where inclined planes are there, we resolve the weight of the vector that is Fgrav into two components. The gravity force will be resolved into two components of force again that are – one which is directed parallel to the inclined surface and the other- which is directed perpendicular to the inclined surface. 

[Image will be uploaded soon]


Simplifying Problems of Inclined Plane 

In the friction or the presence of friction or other forces that are applied force or the tensional forces etc  a slight situation is more complicated. Consider the diagram shown below. Yet the force which is frictional force must also be considered when determining the net force. As in all problems of net force, the net force is the vector sum of all the forces which are present. That is we can see that all the individual forces are added together as vectors. The components which are perpendicular and the normal force add to 0 N. The components which are parallel components and the friction force add together to yield 5 N. The net force is 5 N, which is directed and the incline towards the floor.

The above problem and all planes which are inclined plane problems can be simplified through a useful trick which is known as "tilting the head." So to transform the problem back into the form with which we are more comfortable merely tilt our head in the same direction that the incline was tilted. Or we can do other better things yet merely tilt the page of paper and a sure remedy for TNS - "tilted neck syndrome" or "taco neck syndrome" so that the surface no longer appears in the level it was earlier. 

This is illustrated in the below diagram: 

[Image will be uploaded soon]


Acceleration 

In mechanics the process of acceleration is the rate of change of the velocity of an object with time. Accelerations can be determined as they are vector quantities in which they have magnitude and direction. The object's orientation acceleration is given by the orientation of the net force which is acting on that object. The objects magnitude acceleration as described by sir Newton's Second Law is the combined effect of two causes mentioned below:

  • The balance which is net balance of all external forces that are acting on that object — magnitude is directly proportional to the net force

  • That mass of object which is depending on the materials out of which it is made — magnitude is inversely proportional to the mass of the object.

If we see the example when a vehicle starts from a standstill position that is zero velocity in an inertial frame of reference and travels in a straight line at increasing speeds and it is accelerating in the travel direction. 


In an Inclined Plane Forces and Acceleration 

A mass of 4 kg is released on a frictionless slope which is at an angle of 30o to the horizontal.  Gravity here which causes the mass to accelerate down from the slope.  But the force of gravity or W which acts vertically downwards itself.  So the force causes the acceleration  component of the force of gravity acting down the slope denoted by  (FD).

The gravity  force is resolved into two components that are denoted as  FD and which is parallel to the slope which is  FP perpendicular to the slope.

[Image will be uploaded soon]

Here W = mg = 4 x 9.8 = 39.2 N

Here FD = mg sin 30o = 39.2 x sin30o = 19.6 N

Here FP = mg cos 30o = 39.2 x cos30o = 33.9 N

And FP presses the object and that too against the slope and it is balanced by the normal reaction force that is denoted as R.the unbalanced force which is causing the acceleration that is FD.

[Image will be uploaded soon]

FAQs on Acceleration on an Inclined Plane Explained

1. What is meant by acceleration on an inclined plane?

Acceleration on an inclined plane is the rate at which an object's velocity changes as it moves along a tilted surface. This acceleration is primarily caused by the component of gravitational force that acts parallel to the surface of the incline. On a smooth, frictionless plane, this is the only force causing the motion down the slope.

2. What is the formula to calculate the acceleration of an object on a smooth inclined plane?

The formula for the acceleration of an object on a smooth (frictionless) inclined plane is given by: a = g sin(θ). In this formula, 'a' represents the acceleration down the incline, 'g' is the acceleration due to gravity (approximately 9.8 m/s² on Earth), and 'θ' (theta) is the angle the inclined plane makes with the horizontal.

3. How does the angle of inclination affect an object's acceleration?

The angle of inclination has a direct and significant impact on acceleration. As the angle 'θ' increases, the value of sin(θ) also increases. Since acceleration is directly proportional to sin(θ), a steeper incline results in a greater acceleration. For example, if the plane is horizontal (θ = 0°), the acceleration is zero. If the plane is vertical (θ = 90°), the acceleration is equal to 'g', as the object is in free fall.

4. What are some real-world examples of inclined planes?

Inclined planes are simple machines used to make work easier. Common real-world examples include:

  • Ramps: Used for wheelchair access, loading goods onto trucks, or as entrance/exit ramps on highways.

  • Slides: Found in playgrounds, where gravity pulls a person down the inclined surface.

  • Stairs: A set of connected inclined planes that allow vertical movement with less effort.

  • A Screw: Essentially an inclined plane wrapped around a central cylinder.

5. Why does an object accelerate down an inclined plane instead of falling straight down?

An object on an inclined plane accelerates down the slope because its weight (the force of gravity, mg) is resolved into two separate components. The component perpendicular to the plane (mg cos θ) is balanced by the normal force from the plane's surface. However, the component parallel to the plane (mg sin θ) is an unbalanced force that pulls the object along the surface, causing it to accelerate down the incline rather than falling directly through the plane.

6. How does friction change the acceleration of an object sliding down an inclined plane?

Friction is a force that always opposes motion. When an object slides down an inclined plane, the force of kinetic friction acts up the slope, directly against the parallel component of gravity. This reduces the net force acting on the object. Consequently, the acceleration is reduced. The formula becomes a = g(sin(θ) - μₖcos(θ)), where μₖ is the coefficient of kinetic friction. If the frictional force is large enough, it can even prevent the object from accelerating at all.

7. What is the importance of distinguishing between the parallel and perpendicular components of gravity on an incline?

Distinguishing between the two components is crucial for correctly analysing the forces at play:

  • The parallel component (mg sin θ) is the 'action' component. It is the net force that causes the object to accelerate along the incline. Without this component, the object would remain stationary.

  • The perpendicular component (mg cos θ) is the 'interaction' component. It determines the magnitude of the normal force exerted by the plane on the object. This normal force is, in turn, critical for calculating the force of friction (since Friction = μN).

8. If an object is pushed up a smooth inclined plane and then released, is its acceleration different when going up versus coming down?

No, on a smooth (frictionless) inclined plane, the acceleration of the object is the same in both magnitude and direction, whether it is moving up or sliding down. In both cases, the only force acting along the incline is the parallel component of gravity (mg sin θ), which always points down the slope. This constant downward acceleration will slow the object down as it moves up, bring it to a momentary stop, and then cause it to speed up as it slides back down.

<h2>Motion and Forces on Inclined Planes</h2> <p><strong>Summary:</strong> An inclined plane (ramp) is one of six simple machines where objects accelerate due to unbalanced forces. The normal force isn't directed upward as usual but perpendicular to the inclined surface. Gravity force must be resolved into two components: parallel and perpendicular to the incline. The parallel component causes acceleration down the slope, while the perpendicular component is balanced by normal reaction force. Problems can be simplified by "tilting the head" to reorient perspective. Acceleration depends on net external forces and object mass according to Newton's Second Law. In the example given, a 4kg mass on a 30° frictionless slope experiences 19.6N force down the slope (mg sin 30°) and 33.9N perpendicular force (mg cos 30°), with total weight of 39.2N.</p> <h3>Questions/Concepts Covered:</h3> <ul> <li>How are gravity forces resolved on inclined planes and what causes object acceleration?</li> <li>What is the relationship between normal force direction and inclined plane orientation?</li> <li>How do you calculate force components and acceleration on frictionless inclined surfaces?</li> </ul> <h3>Keywords:</h3> <ul> <li>Inclined plane force resolution</li> <li>Normal force perpendicular component</li> <li>Gravity acceleration down slope</li> <li>Newton's second law mechanics</li> <li>Frictionless inclined plane motion</li> </ul>