Question

3. A train accelerates uniformly from 36km/h to 72 km/h in 20 sec. Find
the distance travelled.​

Answer 1

Answer:

plzz mark as brainlist

Explanation:

Initial velocity = 36 km/hr

Final Velocity = 72 km/hr

Time taken = 10 seconds

To find:

Distance travelled.

Conversion :

Convert unit of velocity from km/hr to

m/s.

1. 36 km/hr = 36 × 5/18 = 10 m/s

2. 72 km/hr = 72 × 5/18 = 20 m/s

Calculation:

Acceleration be denoted as "a"

\therefore \: a = \dfrac{v - u}{t}∴a=

t

v−u

= > a = \dfrac{20 - 10}{10}=>a=

10

20−10

= > a = 1 \: m {s}^{ - 2}=>a=1ms

−2

Now distance travelled :

\begin{gathered}\therefore \: s = ut + \frac{1}{2} a {t}^{2} \\ = > s =( 10 \times 10) + ( \dfrac{1}{2} \times 1 \times {10}^{2} ) \\ = > s = 100 + 50 \\ = > s = 150 \: metres\end{gathered}

∴s=ut+

2

1

at

2

=>s=(10×10)+(

2

1

×1×10

2

)

=>s=100+50

=>s=150metres

So final answer :

\boxed{ \red{distance = 150 \: metres}}

distance=150metres

Additional information on velocity:

1. It is a vector quantity.

2. It has both directions and magnitude.

3. It is also called the rate of change of Displacement.