Question

1. A train accelerates at a rate of 5 m/s? How long does it take to reach its top velocity of 90 km/h, starting from rest? fardoor the​

Answer 1

Given :

Initial velocity, u= 0m/s ( Starts from rest)

Final velocity, v= 90km/h = 90 × \dfrac{5}{18}

18

5

= 25m/s

Acceleration, a= \bold{ 5 m/s^{2} }5m/s

2

To find:

Time taken to reach its top velocity= ?

\boxed{\boxed{\bold{Solution:}}}

Solution:

According to the equation of motion :

v = u + at

⇒25= 0 + 5 × t

⇒25= 5t

⇒25÷ 5 = t

⇒\boxed{\boxed{\bold{t = 5 seconds}}}

t=5seconds

∴Time taken to reach its top velocity= \boxed{\bold{5seconds}}

5seconds

For Information:

To find the distance travelled by the train in 5 second : ?

\bold{S= ut + \dfrac{1}{2} at^{2} }S=ut+

2

1

at

2

⇒S= 0 × 5 + \dfrac{1}{2}

2

1

× 5 × 5 × 5

⇒S= 0 + 312.5

⇒S =\boxed{ \bold{312.5m }}

312.5m