Different Scalars and Vectors

1 (c) List the vectors and scalars from distance, displacement, length, speed, velocity, time, acceleration, mass and force.

I already explained the terms scalars and vectors in my post here. It is extremely easy to differ between a scalar and a vector, and to pick them out once you have understood the two terms. I'll now explain how each of the quantities listed above is a scalar or a vector.

• Distance

Distance can be defined as the space between two fixed points. It has a magnitude i.e 5, and a unit km. But it has no specific direction.

• Displacement

 Displacement can be defined as the shortest distance between two points. As the shortest distance is always in a straight line, it has a direction. Therefore it is a vector. Remember both distance and displacement have the same unit. To better help you understand the difference between distance and displacement, I'll present a scenario to you.

A car travels from Multan to Lahore over a total distance of 300 km. Now, the car does not travel in a straight direction towards Lahore from Multan, but has to travel by road.

You can see the car does not have any particular direction while going by road. Now if an airplane was going to Lahore instead, it would travel in a straight direction.

• Length

Length does not have any direction. Therefore it is a vector.

• Speed

Speed is the rate of change of distance. As i explained earlier that distance is a scalar, so speed is a scalar too as it is derived from distance.Also, the other quantity speed is made of is time. It is obvious that time does not have any direction. Thus speed is a scalar.

• Velocity

Velocity is rate of change of displacement. Now we know that displacement is a vector quantity as it has a specific direction. Thus velocity too is a vector. Remember that speed and velocity have the same unit.

• Time

Time is obviously a scalar quantity as it does not have any direction.

• Acceleration

Acceleration is rate of change of velocity. We know that velocity is a vector, as it is in a particular direction. Thus acceleration too is a vector, as it is in a particular direction too.

• Mass

Mass is defined as the amount of matter in a body. It can not have any direction. Thus it too is a scalar.

• Force

Force is a vector. This is so because force is always applied in some direction, e-g weight is in downwards direction, air resistance is against the movement of the body etc.