a)
The two slanted dipoles exert a force on the central dipole. Let the force makes an angle with the horizontal, then the horizontal forces exerted by two slanted dipoles on central dipole cancel each other. The two vertical forces exerted by two slanted dipoles on central dipole add up to make , which acts vertically upwards on central dipole.
Hence opposes the downward external force .
b)
The positive charge on left most dipole attracts the negative charge on central dipole . The negative charge on right most dipole attracts the positive charge on central dipole.
The left dipole pulls the central dipole with a force towards left , and the right dipole pulls the central dipole with a force towards right. So the central dipole cannot move either to left or to right as equal forces are acting on it in two opposite directions.
Hence the adjacent dipoles attract each other, and cannot be separated.
9. As a simple model of surface tension, the surface of a polar liquid, like water,...
3. Surface tension of a water strider For an animal the size of a human, surface tension seems to be a rather small and insignificant force (though it plays an important if unnoticed role in our breathing). But as animals get smaller, surface tension gets increasingly significant. (The weight of the animal goes down with the cube of the size while the surface tension only decreases linearly.) For animals like the basilisk lizard and the jacana (bird), they appear to...
3. Surface tension of a water strider For an animal the size of a human, surface tension seems to be a rather small and insignificant force (though it plays an important if unnoticed role in our breathing). But as animals get smaller, surface tension gets increasingly significant. (The weight of the animal goes down with the cube of the size while the surface tension only decreases linearly.) For animals like the basilisk lizard and the jacana (bird), they appear to...
3. Surface tension of a water strider For an animal the size of a human, surface tension seems to be a rather small and insignificant force (though it plays an important if unnoticed role in our breathing). But as animals get smaller, surface tension gets increasingly significant. (The weight of the animal goes down with the cube of the size while the surface tension only decreases linearly.) For animals like the basilisk lizard and the jacana (bird), they appear to...
3. Surface tension of a water strider For an animal the size of a human, surface tension seems to be a rather small and insignificant force (though it plays an important if unnoticed role in our breathing). But as animals get smaller, surface tension gets increasingly significant. (The weight of the animal goes down with the cube of the size while the surface tension only decreases linearly.) For animals like the basilisk lizard and the jacana (bird), they appear to...
Question 3. A-C 3. Surface tension of a water strider For an animal the size of a human, surface tension seems to be a rather small and insignificant force (though it plays an important if unnoticed role in our breathing). But as animals get smaller, surface tension gets increasingly significant. (The weight of the animal goes down with the cube of the size while the surface tension only decreases linearly.) For animals like the basilisk lizard and the jacana (bird),...