Why couldn’t the Mars science laboratory land using airbags to bounce to the Martian surface from a parachute

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.

Calculate the bore of a cylinder that has a stroke of 18 inches and an extension time of 6 seconds at a flow rate of 4 gal/min.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.