Question

4. A train starts from rest and accelerates uniformly for 5 minutes. If it attains a velocity of 90 km/s, find its acceleration.​

Answer 1

Answer :

Given -

• Time = 5 minutes = 5*60 = 300 s
• u = 0 m/s
• v = 90 km/s = 90,000 m/s
• Accelerates uniformly

To Find -

• Acceleration ?

Solution -

Acceleration is said to be rate of change of velocity.

So, a = (v - u)/t

⇒ a = (90,000 - 0)/300

⇒ a = 90,000/300

⇒ a = 900/3

⇒ a = 300 m/s²

Hence, Acceleration gained by the train after starting is 300 m/s².

Answer 2

Explanation:

ANSWER:-

GIVEN:-

Initial velocity = 0 km/s

Final velocity = 90 km/s = 90,000m/s

Time = 5 minutes = 60×5=300 seconds

Acceleration = ?

We know that

$a = \frac{v - u}{t}$

• Where a is acceleration
• v is final speed
• u is initial speed
• T is time

$a = \frac{90000 - 0}{300}$

$a = \frac{90000}{300}$

$a = \frac{900}{3}$

a = 300 m/s² is the answer

Things to note:-

• Convert all the units to SI Units
• km/s is taken as m/s or km/h.
• u is zero because it started from rest as given in the question.