It is easier to swim in sea water than in a river because, the sea water contains salt which increases the density of water and also increases its upthrust so, the body sinks less in it and we swim easily ...
Archimedes principle, the weight of water displaced by any
body equals the weight of the floating body. In sea water,
as density is more, less volume of water has to be displaced
for a swimmer to float. Hence, it is easier to swim.
a truck A moving with a velocity of 30m/s collides with a
stationary trolley B of mass 0.5tonnes after collision the
two bodies were automatically connected.find their common
velocities after collision if the mass of truck is 1.2tonne.