The displacement is the vector with
magnitude
distance between position at 5 sec and position at 8 sec
and direction
direction from position at 5 sec to position at 8 sec .
The route followed during the time interval is irrelevant.
Answer: 2.67 m/s
Explanation:
Given
Mass of block A is 
mass of block B is 
The initial velocity of block A 
the initial velocity of block B is 
After collision velocity of block A is 
Conserving momentum

The momentum of block A after the collision is 
Therefore, there is no change in sign.
Answer:
Under normal conditions, a magnetic material like iron doesn't behave like a magnet because the domains don't have a preferred direction of alignment. On the other hand, the domains of a magnet (or a magnetized iron) are all aligned in s specific direction.
Answer:
the volume of liquid decreased due to evaporation from the exposed free surface of water so molecules got evaporated .
evaporation occurs at room temperature.