Question

5. A rabbit carries its food back home. It has a velocity 72 km/h for 5 seconds, rests for 35seconds and continues moving and reaches home in 10 seconds with velocity 20m/s .Calculate its average speed.​

Answer 1

✬ Answer:- ✬

Given:-

• Case ¹ ➯ v = 72 km/h = 20 m/s [Multiply the speed value given in km/h with 5/18]

t = 5 s

• Case ² ➯ v = 0 m/s (rest)

t = 35 s

• Case ³ ➯ v = 20 m/s t = 10 s

To Find:-

Average velocity of the rabbit.

______________...

Finding distance of Case ¹, ² and ³.

Case ¹:

s = vt

⟹ s = (20 m/s)(5 s)

⟹ s = 100 m

Case ²:

s = vt

⟹ s = (0 m/s)(t)

⟹ s = 0 m

Case ³:

s = vt

⟹ s = (20 m/s)(10 s)

⟹ s = 200 m

We know,

Average velocity = (total distance travelled)/(total time taken)

∵ av. v = (200 m + 0 m + 100 m)/(5 s + 35 s + 10 s)

⟹ av. v = (300 m)/(50 s)

⟹ av. v = (30 m)/(5 s)

⟹ av. v = 6 m s⁻¹

∴ Average velocity of the rabbit was 6 m s⁻¹.