Question

A train starting from rest attains a velocity of 20 m/s in 2 minutes. Assuming that the acceleration is uniform, find 1)the acceleration 2)distance travelled by the train, while it attained this velocity? ​

Answer 1

$\textbf{\underline{Answer:-}}$

Given :-

• Velocity = 20m/s
• Time = 2 mins

To Find :-

• Acceleration
• Distance traveled while it attained velocity

Solution :-

(i)

We know that Acceleration = v - u/t

Here,

• u = o
• v = 20
• t = 2min = 120sec

Substituting in Formula :-

A = 20 - 0/120

A = 20/120

Acceleration = 1/6 m/s²

-----------------

(ii)

Using 2nd Law of motion,

s = ut + 1/2at²

Here,

• s = distance
• a = 1/6
• u = 0
• t = 120

Substituting in formula :-

s = 0 x 120 + 1/2 x 1/6 x 120²

s = 0 + 1/12 x 14400

Distance = 1200m

Answer 2

» A train starting from rest attains a velocity of 20 m/s in 2 minutes.

Here..

• Initial velocity (u) = 0 m/s

(As train is at rest)

• Final velocity (v) = 20 m/s

• Time (t) = 2 min

=> 2 × 60

=> 120 sec

____________ [ GIVEN ]

• We have to find the acceleration (a) of the train.

_____________________________

We know that

v = u + at

Put the known values in above formula

→ 20 = 0 + a(120)

→ 120a = 20

→ a = 20/120

→ a = 1/6

____________________________

→ a = 0.16667 m/s²

_________ [ ANSWER ]

_____________________________

Now.. we have

• Acceleration (a) = 0.16667 m/s²

• Time (t) = 120 sec

• Initial velocity (u) = 0 m/s

__________ [ GIVEN ]

• We have to find the distance (s) travelled by the train.

____________________________

We know that

s = ut + 1/2at²

Put the known values in above formula

→ s = (0)(120) + 1/2 (0.167)(120)²

→ s = 0 + 1/2 (0.16667)(14400)

→ s = 1/2 (2400.048)

→ s = 1200.024 m

→ s = 1200 m (approx.)

___________________________

Distance travelled by train is 1200 m

_________ [ ANSWER ]

___________________________