Question

a train starts from rest with an acceleration of 2m/s a man who is 9m
behind the train runs with uniform speed and just manages to get into train in 10 seconds The speed of the manage ​

Answer 1

Complete Question :-

• Train starts from rest with an acceleration of 2m/s². A man who is 9m behind the train runs with uniform speed and just manages to get into train in 10sec. The speed of the man ?

Given data :-

• A train starts from rest with an acceleration of 2m/s²
• Man catches train in 10s with crossing 9m distance.

To find :- Speed of man ?

Solution:-

As per given man catches train in 10sec mean train travell distance ( s ) in 10sec.

Let, distance travelled by train be ' s '

acceleration = a; initial velocity = u;

final velocity = v; time = t

Here,

→ a = 2 m/s²

→ u = 0

→ t = 10 sec

To find final velocity of train

→ v = u + at

→ v = 0 + 2 × 10

→ v = 0 + 20

→ v = 20 m/s

Now, to find distance travelled by train

→ v² = u² + 2as

→ v² - u² = 2as

→ (20)² - 0 = 2 × 2 × s

→ 400 = 4 × s i.e.

→ s = 400/4

→ s = 100 m

Now, total distance travelled by man

→ Total distance = s + 9

→ Total distance = 100 + 9

→ Total distance = 109 m

Now, we know man cover 109m in 10sec.

Hence, now for speed of man

→ speed of man = distance/time

→ speed of man = 109/10

→ speed of man = 10.9 m/s

Hence speed of man is 10.9m/s.