Loft insulation costs £50 to install but you save £10 a year on your bills. Wall insulation costs £150 to install but you save £5 per year. Double glazing costs £12,000 to install but you save £70 a year. Which would you install if you were only planning in living in your house for another 2 years? Explain your choice.

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?