Find the acceleration of blocks and tension in the cord in the device shown in fig. Assume no friction anywhere.

Explanation

By Newton's second law

`4g sin 30-T=4a` …(i)
and `T=-1g=1a` ..(ii)
solving eqs (i) and (ii), we get
`a=2ms^(-2) and T=12N`
By shortcut Method:
`a=("Unbalanced load")/("Total mass")=(4g sin 30^(@)-1g)/(4+1)=2ms^(-2)`
`T=M_(up)(g+a)=1(10+2)=12N`.