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...
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.
#include<stdio.h>
#include<conio.h>
#include<string.h>
int main() {
int i, number, num1, num2=0;
char str1[50];
num1 = number;
for(i=2; i<=20; i+=2) {
printf("%d", i);
printf(", ");
}
return 0;
}
