Answer, and give a reason. Why are rubber pads placed under heavy machines and in shock absorbers?

Step 1. (a) Each time rubber is squeezed and released, the loop in its stress-strain graph turns some energy into heat. The pads soak up vibration instead of passing it on.

Step 2. (b) Steel: it needs a far larger stress for the same strain, so it opposes deformation more strongly.

Step 3. (c) Elastic fatigue: repeated stress, especially past the elastic limit, weakens the metal until it fails below its normal breaking stress.