A dynamometer D is attached to weights of mass M = 10 kg and m = 10 g. Force F=20 N and 10 N are applied to the weights. What will happen to the weights and what will the dynamometer show if:
The force F is applied to larger weight and f to smaller weight.

Explanation

In all the cases as net pulling force is F -f, while the mass involved is m+ M.
Acceleration (a) `("force")/("mass")=(F-f)/(m+M)=1(m)/(s^2).......(i)`
So, the whole system will inove in the direction of larger force with acceleration given by Eqn. (i)
lf `T_1` is the reading of dynamometer then for motion of M and m respectively, we have
`F-T_1=Ma` and `T_1-f=ma`
i.e., `T_1=F-Ma` and `T_1=f+ma`
Substituting a from Eqn. (i) in any of the above, we get
`T_1=(mF+Mf)/(m+M)=f=10N` ......(ii)