A long time back when I was a teenager (in the 17th century) and water balloons and Holi had just been invented this is what we did. We’d half fill the balloons with dirt or sand first and then top it up with coloured water. So that when we threw it at someone not only would they get wet but also filthy. Luckily cops hadn’t been invented then.
So, partially fill a rubber balloon with sand and water so that there is more than enough water to cover the sand but not enough to fill the balloon. Now tie up the top and try to squeeze the balloon. You’ll find it’s easy at first but as you continue to squeeze, you’ll find a point where the balloon just refuses to bulge even though you’re squeezing as hard as you can. What causes this sudden and determined resistance to further squeezing?
THROUGHPUT
(The tough-nut of the week before yesterweek concerned two ropes hanging from a ceiling and a skilled acrobat had to cut them in such a way as to max out the length.)
The acrobat climbs up rope #1. Swings himself onto rope #2 (not letting go of rope #1). He cuts rope #2 at the highest point. He now has all of rope #2, and is swinging free on rope #1. He ties rope #1 at the very top near the ceiling into a loop (say he needs about a foot of rope for this). He hangs on the loop and cuts all the rope below the loop. He now ties rope #2 and rope #1 into a single rope, passes it through the loop, and gets down that way. Once on the floor he just pulls this rope #1 + rope #2 combination out of the loop, and merrily skips away. -- Altaf Ahmed, ctrlaltaf@yahoo.in
(An even earlier one was: “Two identical cars collide head on. Each car is travelling at 100 kmph. The impact force on each is the same as hitting a solid wall at what speed?”)
Since the collision is head on and each car is identical and travelling at the same speed, the force of impact experienced by each car is equal and opposite. This means that the impact is the same as hitting a solid wall at 100 km/h. -- Dhruv Narayan, dhruv510@gmail.com
(The third one was: “A and B have two identical drinks consisting of 30 ml whisky, 60 ml water and one ice cube each. One of the drinks is lethally poisoned. A gulps it down and B lingers over it for half an hour. None of them dies. Whose drink was poisoned?”)
A’s drink was poisoned. The poison is in the ice-cube of one of the drinks. A gulped it down before the poisoned ice-cube melted and contaminated his drink. He survived. B had no problem nurturing his drink for half an hour since his drink was not poisoned! -- Wg Cdr Raju Srinivasan, rajusrinivasan@gmail.com
The poison which is in the ice cube gets diluted by the melting of the ice to a sub-lethal dose and so the one who nursed his drink for half an hour, did not die. The gulper of course did not have the spiked drink. What if the drinks were served in an al fresco party in the Antarctica! -- Dr Ramakrishna Easwaran, drrke12@gmail.com
(Among the first five to also get it correct are: Aravind Suresh, aravind.suresh@hotmail.com; Rajesh R, rajesh56rr@gmail.com; Abhay Prakash, abhayprakash@hotmail.com; Saishankar Swaminathan, saishankar482@gmail.com; K Sathyadev, sathya2008k@gmail.com)
(The fourth puzzle was the logic one which ended with the queries: “So what colour are the heart tablets and who takes them for nerves?”)
A little juggling with the data with the conditions specified yield the solution as follows. A: heart (yellow) and sleeplessness (white); B: nerves (blue) and kidney (red); C: heart (yellow) and indigestion (green); D: kidney (red) and nerves (blue ); E: indigestion (green) and sleeplessness (white). -- A V Ramana Rao, raoavr@gmail.com
BUT GOOGLE THIS NOW
1. Remember some tin containers which you had to heat when their lids got stuck and wouldn’t come off? Question: What difficult problem’s answer does this illustrate?
2. A man can walk up a moving ‘up’ escalator in 30 seconds. He can walk down the same moving ‘up’ escalator in 90 seconds. His walking pace is the same while climbing up or down. (a) How long would it take for him to climb up the escalator if it is stationary? (b) How long would it take for him to go up the moving escalator if he stood still? (Submitted by Dr P Gnanaseharan, gnanam.chithrabanu@gmail.com)
Sharma is a scriptwriter and former editor of Science Today magazine.(mukul.mindsport@gmail.com)