A body starts from rest at time $t = 0$, the acceleration time graph is shown in the figure. The maximum velocity attained by the body will be

Step 1: Identify the initial conditions.

The body starts from rest, and the acceleration decreases linearly from $10\text{ m/s}^2$ to $0$ over $11\text{ s}$.

$$u = 0 \text{ at } t = 0$$ $$a(0) = 10\text{ m/s}^2$$ $$a(11) = 0$$

Step 2: Determine the time of maximum velocity.

Since the acceleration remains positive for the entire duration, the velocity increases monotonically and reaches its maximum at $t = 11\text{ s}$.

$$a(t) \ge 0 \quad \text{for} \quad 0 \le t \le 11\text{ s}$$

Step 3: Calculate the maximum velocity using the area under the curve.

The change in velocity is equal to the area of the triangle under the $a$-$t$ graph.

$$v_{\max} = \frac{1}{2} \times \text{base} \times \text{height}$$ $$v_{\max} = \frac{1}{2} \times 11\text{ s} \times 10\text{ m/s}^2$$ $$v_{\max} = 55\text{ m/s}$$

Answer: The maximum velocity attained by the body is $55\text{ m/s}$.