Question

Calculate the initial velocity of a train which is stopped in 50 seconds by applying breaks. The retardation is 5m/s^2.

Answer 1

Given

Calculate the initial velocity of a train which is stopped in 50 seconds by applying breaks. The retardation is 5 m/s²

To Find

Initial velocity

Solution

We know that

$\sf \longrightarrow u=v-at$

Here

• u = Initial velocity
• v = Final velocity
• a = Acceleration
• t = Time

According to the question

We are asked to find "u"

Given that

• v = 0 m/s [stars from rest]
• a = -5 m/s²
• t = 50 s

Substituting the values

We get

$\sf \longrightarrow u=0-(-5) \times 50 \ m/s$

$\sf \longrightarrow u=+5 \times 50 \ m/s$

Therefore

$\sf \longrightarrow u=250 \ m/s$

Hence

Initial velocity = 250 m/s

Answer 2

Answer:

Given :-

• A train which is stopped in 50 seconds by applying breaks.
• The retardation is 5 m/s².

To Find :-

• What is the initial velocity of a train.

Formula Used :-

$\boxed{\bold{\large{u\: =\: v\: -\: at}}}$

where,

• u = Initial velocity
• v = Final velocity
• a = Acceleration
• t = Time

Solution :-

Given :

• Acceleration = 5 m/s²
• Time = 50 seconds
• Final velocity = 0 m/s

According to the question by using the formula we get,

⇒ u = v - at

⇒ u = 0 - (5) × 50

⇒ u = - 5 × 50

➥ u = - 250 m/s

We can't take initial velocity as negative.

$\therefore$ The initial velocity of a train is 250 m/s .