GIVEN:
Amplitude, A = 0.1mm
Force, F =1 N
mass of motor, m = 120 kg
operating speed, N = 720 rpm
=
Formula Used:

Solution:
Let Stiffness be denoted by 'K' for each mounting, then for 4 mountings it is 4K
We know that:

so,
= 75.39 rad/s
Using the given formula:
Damping is negligible, so, 
will give the tranfer function
Therefore,
= 
= 
Required stiffness coefficient, K = 173009 N/m = 173.01 N/mm
Complete Question
The complete question is shown on the first uploaded image.
Answer:
The answer is shown on the second uploaded image
Explanation:
The explanation is also shown on the second uploaded image
Answer:
d. 90%
Explanation:
As we know that internal combustion engine produce lot's of toxic gases to reduce these toxic gases in the environment a device is used and this device is know as current modeling converter.
Generally the efficiency of current model catalytic converter is more than 90%.But the minimum efficiency this converter is 90%.
So option d is correct.
d. 90%
I’m a concrete mason myself and I can tell you it is a pain in the butt to Roto hammer a hole into the concrete to put the pipe in it’s a lot easier to just pour the concrete around it