Reema started from rest and increased her speed uniformly at 4 m/s². How much time will she take to complete 2 rounds of a rectangular field which is 400 m?

To find the time it takes for Reema to complete 2 rounds of the rectangular field, we can use the equation:

distance = initial velocity * time + (1/2) * acceleration * time^2

In this case, the initial velocity is 0 m/s since Reema starts from rest, the acceleration is 4 m/s², and the distance is 400 m.

Since Reema completes 2 rounds of the field, the total distance she covers is 2 times the perimeter of the rectangular field, which is 2 * (2 * length + 2 * width).

Let's assume the length of the rectangular field is L and the width is W. We can then write the equation:

2 * (2 * L + 2 * W) = 400

Simplifying this equation, we get:

4 * (L + W) = 400

Dividing both sides by 4, we have:

L + W = 100

Since we don't have the specific values for the length and width of the field, we cannot solve for L and W individually. However, we can make an assumption to proceed with the calculation.

Let's assume the length and width are equal, so L = W = 50.

Substituting these values back into the equation, we have:

50 + 50 = 100

Now we can calculate the time it takes for Reema to complete 2 rounds of the field using the equation mentioned earlier:

distance = initial velocity * time + (1/2) * acceleration * time^2

400 = 0 * time + (1/2) * 4 * time^2

Simplifying this equation, we get:

400 = 2 * time^2

Dividing both sides by 2, we have:

200 = time^2

Taking the square root of both sides, we find:

time = √200

Using a calculator, we can approximate the square root of 200 to be around 14.14.

Therefore, Reema will take approximately 14.14 seconds to complete 2 rounds of the rectangular field.