Vectors and scalar quantities

Question 1

Question: What is the difference between scalar and vector quantities?

Answer 1

Scalar quantity: A value with magnitude only (e.g., 3 kg).

Vector quantity: A value with both magnitude and direction (e.g., velocity, displacement).

Question 2

Question: How is velocity different from speed in physics?

Answer 2

Speed: The magnitude of how fast something is moving (e.g., 5 m/s).

Velocity: Includes both speed and direction (e.g., 5 m/s north).

Question 3

Question: What is displacement in physics, and how does it differ from distance?

Answer 3

Displacement: The shortest path between the starting and ending points, with direction. It is a vector.

Distance: The total length of the path traveled, regardless of direction. It is a scalar.

Question 4

Question: If you walk in a circle and return to the starting point, what are the distance and displacement?

Answer 4

Distance: The total length of the circle (2πr).

Displacement: Zero, because the starting and ending points are the same.

Question 5

Question: What is acceleration, and why is it considered a vector quantity?

Answer 5

Acceleration is the rate of change of velocity and has direction, which makes it a vector.
It can point in the same direction as velocity or the opposite direction (as in deceleration).

Question 6

Question: Why is time considered a scalar quantity?

Answer 6

Time has no spatial direction—it only progresses forward or backward. In physics, spatial direction is required for a vector, making time a scalar.

Question 7

Question: What happens when you multiply scalar and vector quantities?

Answer 7

Multiplying a scalar by a scalar gives a scalar.

Multiplying a vector by a scalar gives a vector.

Multiplying vectors together can result in either a scalar or vector depending on the operation.

Question 8

Question: Why are equations involving vectors and scalars important in physics?

Answer 8

These equations help predict the behavior of physical objects, such as their motion, speed, and acceleration. They are essential for understanding how objects move and interact.

Question 9

Question: If a car is traveling at 13.9 m/s and stops within 1.75 seconds, what is its acceleration? Answer:

Answer 9

using the formula a=vf-vi/t

a = 0-13.0/1.75

The car’s acceleration is −7.94m/s^2 , indicating it is slowing down.

Question 10

Question: In one-dimensional motion (e.g., a car moving on a straight road), is it necessary to break the motion down into X and Y components?

Answer 10

No, for straight-line motion in one dimension, there’s no need to break it into components. The entire motion can be treated along a single axis.