Question

A particle travels 10 min first 5 seconds 10 min next 3 seconds. Assuming constant acceleration what is the
distance travelled in next 2 second :
(A) 8.3 m
(B) 9.3 m
(D) none of these​

Answer 1

Answer:

Explanation:

Solution,

Here, According to 2nd equation of motion,

We know that,

s = ut + 1/2at²

So, putting the valves, we get

In 1st case,

s = ut + 1/2at²

⇒ 10 = u × 5 + 1/2 × a × (5)²

⇒ 10 = 5u + 25a/2

⇒ 2u + 5a = 4 .... (i)

Now, In 2nd case,

Putting all the values again, we get

Here, we will take total distance covered and total time taken,

s = ut + 1/2at²

⇒ 20 = 8u + 1/2 × a × (8)²

⇒ 20 = 8u + 16a/2

⇒ 2u + 8a = 5 ..... (ii)

Now, Solving Eq (i) and (ii), we get

2u + 5a = 4

2u + 8a = 5

-      -        -

__________

⇒ - 3a = - 1

⇒ a = 1/3

Now, putting u's value in eq (i), we get

⇒ 2u + 5a = 4

⇒ 2u + 5(1/3) = 4

⇒ u = 7/6.

Now, distance covered,

s = ut + 1/2at²

⇒ s = 10u + 1/2 × a × (10)²

⇒ s = 10 × 7/6 + 1/2 × 1/3 × 100

⇒ s = 28.3 m.

Distance travelled in next 2 seconds = 28.3 - 20 = 8.3 m.

Hence, the Distance travelled in the next 2 seconds is 8.3 m.