Question 1

What is the SI unit of acceleration?

Accepted Answer

m/s^2. Acceleration is the rate of change of velocity per unit time. Velocity has unit m/s, so dividing by s gives m/s^2. Therefore, m/s^2 is the SI unit.

Question 2

A body starts from rest and accelerates uniformly at 2 m/s^2 for 5 s. How much distance does it cover?

Accepted Answer

25 m. Use s = ut + (1/2)at^2 with u = 0, a = 2, t = 5. So s = 0 + (1/2)×2×25 = 25 m. Hence, 25 m is correct.

Question 3

Which statement is correct about distance and displacement?

Accepted Answer

Distance is a scalar, displacement is a vector. Distance depends on total path length and has only magnitude, so it is scalar. Displacement depends on initial and final position with direction, so it is vector. Distance is never negative, but displacement can be negative in 1D based on direction.

Question 4

In a velocity–time graph, what does the slope represent?

Accepted Answer

Momentum. Slope means change in velocity divided by change in time. That quantity is acceleration by definition. So the slope of a v–t graph gives acceleration.

Question 5

A person walks 3 km at 3 km/h and returns 3 km at 6 km/h. What is the average speed for the whole trip?

Accepted Answer

3 km/h. Average speed = total distance / total time. Time out = 3/3 = 1 h and time back = 3/6 = 0.5 h, so total time = 1.5 h. Total distance = 6 km, so average speed = 6/1.5 = 4 km/h, which is option A? Wait, check options: 4 km/h is option A, so A is correct.

Motion — Set 1