Question

The number of degrees of freedom in a planar mechanism having n links and j simple hinge joints is

• A. $3(n-3)-2j$
• B. $3(n-1)-2j$
• C. $3n-2j$
• D. $2j-3n+4$

Answer 1

The correct option is B $3(n-1)-2j$

The relation between the no.of links 'n', lower pair 'j' and higher pair 'h' gives a degree of freedom. For a planar mechanism.
$F=3(n-1)-2j-h$
Here, no higher pair, so, h = 0
$F=3(n-1)-2j$