The mass is 5kg
I hope this helps
If we dissolve salt in water they will reduce the intermolecular forces between water molecule and this will decrease the surface tension.
Surface tension is due to cohesive forces (the forces between molecules of same substance) hence as cohesive forces decreases the surface tension also decreases
Thomson used a beam of negatively charged particles. Using a beam of particles and detecting the scattering of the particles after they hit gold foil.
Day and night is due to the earth rotating. Seasons are due to the earth rotating on a slightly tilted axis, causing light to be shone on different parts of the earth more directly during different parts of the year. Constellations changing throughout the night are because of the earth moving and rotating. Throughout the year, the earth moves, causing us to be facing different directions in different parts of the year. The North Star does't move because it is close to Earth's line of axis, and therefore does not appear to move.
