# Hacktivateed

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## What are the difference between lower pair and higher pair?

Lower pair: “When the two elements of a pair have surface(area) contact while in motion the pair is called a lower pair.” motion then the pair is known as higher pair.”

## Why is a higher pair called a higher pair?

In the matter of connections between rigid bodies, Reuleaux recognized two kinds; he called them higher and lower pairs (of elements). With higher pairs, the two elements are in contact at a point or along a line, as in a ball bearing or disk cam and follower; the relative motions of coincident points are dissimilar.

How does a higher pair have two DOF?

P1=Number of Pairs having one degree of freedom P2=Number of Pairs having two degree of freedom and so on DOF of Planar Mechanism:- In Planar Mechanisms Lower Pairs will have 1DOF and Higher pairs will have 2 DOF.

Why lower pairs are more resistant than higher pairs?

Lower pairs are more resistant than the higher pairs in a plane mechanism. 2. In a 4-bar mechanism (with 4 turning pairs), when the link opposite to the shortest link is fixed, a double rocker mechanism results. Lower pairs are more resistant than the higher pairs in a plane mechanism.

### Which of the following pair is an example of higher pair?

Explanation: The cam and follower is an example of higher pair as it is kept in contact by the forces exerted by spring and gravity.

### Which of the following is example of lower pair?

Lower pair: A pair is said to be a lower pair when the connection between two elements is through the area of contact. Ex. Revolute Pair, Prismatic Pair (Piston and cylinder ), Screw Pair, Cylindrical Pair, Spherical Pair (Ball and socket), Planar Pair, etc.

Which of the following is the best example of higher kinematic pair?

Rolling pair Ball and roller bearings, rolling wheel on a flat surface etc.

What is the DOF of higher pair?

In Figure 4-11c, a rigid body is constrained by a higher pair. It has two degrees of freedom: translating along the curved surface and turning about the instantaneous contact point.

#### What kind of contact can be established for a lower pair?

Detailed Solution. Concept: Lower pair: When the two elements of a pair have a surface contact when relative motion takes place and the surface of one element slides over the surface of the other, the pair formed is known as lower pair. Sliding pairs, turning pairs and screw pairs are the examples of lower pairs.

#### Which forms a higher pair?

Which of the following is a higher pair? Explanation: Belt and pulley are higher pairs as the motion is partly turning and partly sliding between them. 3. When the connection between the two elements is such that only required kind of relative motion occurs, it is known as self-closed pair.

How many links must be there in a simple mechanism?

A simple mechanism consists of minimum four links. 6. A mechanism consisting more than four links is called a compound mechanism. Explanation: A mechanism with four links is known as simple mechanism, and the mechanism with more than four links is known as compound mechanism.

Which one of the following is the best example of higher kinematic pair?

## How is one higher pair replaced by two lower pairs?

From above equation we see that one higher pair can be replaced by the addition of one link and two lower pairs to maintain the same number of degrees of freedom of the chain. Figure (1) below shows two wheels in rolling contact (Higher pair).

## Why is kinematic pair important in theory of machines?

The kinematic pair is very important aspect to understand in theory of Machines. The classification of kinematics pair, the most important one is based on the point of contact. On that basis kinematics pair are of two types. These are Lower pair and higher pair

Which is the best definition of a higher pair?

The definition of higher pair is “two links having point contact or line contact”. Eg. (1) Gear transmission (2) Wheel rolling on a surface. Higher pairs are characterised having 2 degrees of freedom (DOF).

Which is lower pair has one translatory motion?

Prismatic joint is a lower pair which has one directional translatory motion and has degree of freedom = 1. This means Prismatic joint has constraint in 5 directions. Revolute joint has one directional rotational motion and therefore degree of freedom =1. The three translatory and two rotational motions has constraints in the revolute joint.