Question

A train accelerates from 20 km hour to 80 km per hour in 4 minute . How much distance does it cover in this period? Assume that the track are straight.​

Answer 1

Answer:

● 10/3 km or 3.33km

Explanation:

We find the acceleration and then the distance.

• Initial velocity (u) = 20km/h

• Final Velocity (v) = 80km/h

• Time (t) = 4 min = 4/60 = 1/15 h (here we change the time min into hour)

Using 1st equation of Motion

⟹ v = u + at

Putting all the values which is given above

⟹ 80 = 20 + a ×1/15

⟹ a = 80 -20/1/15

⟹ a = 900 km/h²

Now , we have to calculate the distance covered by train So,

By using 2nd Equation of Motion

⟹ S = ut +1/2at².

Putting all the values

⟹ S = 20 ×1/15 + 1/2 × 900 × (1/15)².

⟹ s = 4/3 + 450 + 1/225

⟹ s = 20/15 + 2 km

⟹ s = 10/3 km.

or

⟹ s = 3.33 km

Therefore, The distance covered by train is 10/3 km or 3.33km

Answer 2

Hi there!

Your Answer :-

Use First Equation Of Motion.

$\sf\pink {v = u + at}$

Put the values which are given.

$\sf\blue{80 = 20 + a \times \dfrac{1}{15} }$

$\sf\orange{a = 900 \: km {h}^{2} }$

Now We Can Apply Second Equation Of Motion.

$\sf{s = ut + \dfrac{1}{2} a {t}^{2} }$

$\sf\purple{s = \dfrac{10}{3}km }$