Week 2 - Linear Motion

What is the difference between distance and displacement?

• Distance is a vector, while displacement is a scalar.

• Distance depends on direction, while displacement does not.

• Distance is the total path travelled, while displacement is the shortest straight-line distance from start to end.

• Distance can be negative, while displacement is always positive.

Answer explanation

Distance measures the total path covered, whereas displacement considers only the shortest path in a straight line between the start and end points.

If a car moves with a constant velocity, what can be said about its acceleration?

• It is increasing.

• It is decreasing.

• It is zero.

• It is equal to the velocity.

Answer explanation

Acceleration is the rate of change of velocity. If velocity is constant, there is no change, so acceleration is zero.

Which of the following is an equation of motion?

• 𝑣 = 𝑢 + 𝑎𝑡

• 𝐹 = 𝑚𝑎

• 𝑃 = 𝐼𝑉

• 𝑊 = 𝑚𝑔

Answer explanation

v = u + at is one of the kinematic equations of motion, where v is final velocity, u is initial velocity, a is acceleration, and t is time.

What is the SI unit of acceleration?

• 𝑚/𝑠

• 𝑚/𝑠²

• 𝑘𝑚/ℎ

• 𝑘𝑔⋅𝑚/𝑠²

Answer explanation

Acceleration is the rate of change of velocity, measured in metres per second squared (m/s²).

A car starts from rest and accelerates at 2𝑚/𝑠². What will its velocity be after 5 seconds?

• 5 m/s

• 10 m/s

• 15 m/s

• 20 m/s

Answer explanation

Using v = u + at, where u = 0, a = 2m/s², and t = 5s:
v = 0 + (2×5) = 10m/s.

What happens to displacement when velocity decreases uniformly over time?

• It remains constant.

• It increases.

• It decreases.

• It becomes zero immediately.

Answer explanation

Since velocity is decreasing uniformly, the displacement covered in each time interval also decreases.

Which of the following is true about relative motion?

• Motion is always absolute and does not depend on the observer.

• Relative motion is the motion of an object with respect to another object.

• Relative motion is always equal to the actual motion of an object.

• Relative motion is always zero.

Answer explanation

Relative motion describes how the movement of an object appears to an observer in a different frame of reference.

A runner completes a 400 m circular track and returns to the starting point. What is the displacement?

• 400 m

• 200 m

• 100 m

• 0 m

Answer explanation

Displacement is the shortest straight-line distance from start to end. Since the runner returns to the starting point, displacement is zero.

What happens to velocity when an object accelerates in the opposite direction to its motion?

• Velocity increases.

• Velocity decreases.

• Velocity remains constant.

• Velocity becomes infinite.

Answer explanation

When acceleration is in the opposite direction, it acts as a retardation (deceleration), reducing velocity over time.

Which of the following quantities is a vector?

• Speed

• Distance

• Displacement

• Time

Answer explanation

Displacement has both magnitude and direction, making it a vector quantity, unlike speed or distance, which are scalars.