Velocity is a vector quantity and it is the rate of change of displacement with time or change in speed with direction.
Velocity has both magnitude and direction. So when you are in a car going 70 km/h and another car goes in the opposite direction at 70 km/h their velocities are different.
How?
Consider your car as moving in the positive direction, so its velocity will be 70 km/h and for the car moving in the opposite direction, since the direction is opposite, the velocity of that car will be -70 km/h. This is because, the velocity is a vector quantity that has both magnitude and direction. For one car, the direction is positive and for the other one the direction is negative.
From Boyle's law, the volume of a fixed mass of a gas is inversely proportional to its pressure at constant absolute temperature. Therefore; P1V1 =P2V2; where PV is a constant hence; 12 × 6 = 3× p2 p2 = 72/3 = 24 atm Therefore; the new pressure will be 24 atm
