In the air, there's nothing holding the body of the helicopter still - so the rotor blades spin one direction, but the torque applied to spin the rotors tries to spin the body of the helicopter in the opposite direction. The little rotor on the tail helps keep the body of the helicopter pointed in the same direction.

Balance on a bicycle is a matter of constantly correcting against falls, and it's easier when the speed is higher because the inertia of moving forward overcomes the need for corrective actions.

Its all because of oxytocin. Oxytocin is the love hormone that activates feelings of trust and love between people when it is released in the brain. Whenever Surakshya thinks of her college the production of the oxytocin hormone rises to peak but sadly she cannot express her love in anyway. Because of the fact she is miles away from her college and she is bound to accept the truth that she cannot be there in college at the present time. So, there is no way that she can express her love,...

Water is a vital substance for life on Earth, and it plays numerous important biological roles in living organisms. Some of the key biological roles of water are:

1. Universal solvent: Water is an excellent solvent for many substances, both organic and inorganic. This means that it can dissolve and transport a wide range of nutrients and minerals necessary for the growth and survival of living organisms.

2. Medium for metabolic reactions: Many metabolic reactions in living organisms require water...

It is theoretically possible for a substance to have a negative value of cubical expansivity, which means that the substance would contract rather than expand when the temperature increases. However, it is very rare for a substance to have a negative value of cubical expansivity over a significant range of temperatures.

One example of a substance that has a negative value of cubical expansivity over a limited range of temperatures is water. Water has a positive value of cubical expansivity at...