Question

7. A train increases its speed from 10 ms 'to 30 ms' with an acceleration of 5 ms'. What is
the time taken by the train to do so?
(Ans. 4 seconds)​

Answer 1

Explanation:

t = v-u/a

t = 30-10/5

t = 20/5

t = 4

Answer is 4 seconds

Read my bio and follow

Answer 2

Given :

• Initial velocity of train, u = 10 ms⁻¹
• Final velocity of train, v = 30 ms⁻¹
• Acceleration of Train, a = 5 ms⁻²

To find :

• Time taken by the train to do so, t = ?

Formulae required :

• First equation of motion

        v = u + a t

[ Where v is final velocity , u is initial velocity , a is acceleration and t is time taken by the body ]

Calculation :

Using First equation of motion

→ v = u + a t

→ ( 30 ) = ( 10 ) + ( 5 ) t

→ 30 - 10 = 5 t

→ 20 = 5 t

→ t = 20 / 5

→ t = 4 sec

therefore,

• Time taken by the Train to attain a final velocity of 30 ms⁻¹ from an initial velocity of 10 ms⁻¹ with acceleration 5 ms⁻² is 4 seconds.

Three equations of motion :

• First equation : v = u + a t
• second equation : s = u t + 1/2 a t²
• Third equation : 2 a s = v² - u²

[ Where v is final velocity , u is initial velocity , a is acceleration, t is time taken and s is distance covered by the body ]