Question

A train starting from rest attains a velocity of 80 km h-1 in 5 minutes assuming that the acceleration is uniform find the acceleration and the distance travelled by the train for attaining this velocity cbse solution physics class9

Answer 1

Answer:

a = 2/27 m/s²

s = 3,333.33 metres

Explanation:

Given :

• Initial velocity = u = 0 m/s

• Final velocity = v = 80 km/h = 80×5/18 = 200/9 m/s

• Time taken = t = 5 minutes = 300 seconds

To find :

• Acceleration of the train

• Distance travelled by the train

Using first equation of motion :

V=u+at

200/9=0+a×300

200/9 = 300a

a = 200/9×1/300

a = 2/27 m/s²

Using the third equation if motion :

V²-u²=2as

(200/9)²-0²=2×2/27×s

40000/81=4/27 s

40000/81×27/4

10,000/3

s = 3,333.33 metres

Total distance covered is 3,333.33 metres

Answer 2

Given :

• Initial velocity (u) = 0 km/h = 0 m/s
• Final velocity (v) = 80 km/h = 22.2 m/s
• Time taken (t) = 5 minutes = 5 * 60 = 300 seconds

To Find :

We have to find the uniform acceleration (a) and the distance travelled (S) by the train.

Explanation :

Using First equation of the motion.

⇒ v = u + at

→ 22.2 = 0 + a(300)

→ a = 22.2/300

→ a = 0.074 m/s²

$\rule{200}{2}$

Now, using second equation of the motion.

⇒ S = ut + 1/2 at²

→ s = 0(300) + 1/2 (0.074)(300²)

→ s = 0 + 0.037 × 90000

→ s = 3300 m