Identify the final time value on the x-axis.

The graph starts at $t=0$ s and ends at $t=50$ s.
The total time taken is $\boxed{\text{50 s}}$.

The highest velocity shown on the graph is 30 m/s.
The maximum velocity reached is $\boxed{\text{30 m/s}}$.

The acceleration $a$ is given by the formula $a = \frac{\Delta v}{\Delta t} = \frac{v_f - v_i}{t_f - t_i}$.

Initial velocity ($v_i$) at $t_i = 0$ s is 0 m/s.
Final velocity ($v_f$) at $t_f = 20$ s is 30 m/s.

The acceleration during the first 20 seconds is $\boxed{\text{1.5 m/s}^2}$.

The shape under the graph is a trapezoid. The area of a trapezoid is given by $A = \frac{1}{2} (a+b)h$, where $a$ and $b$ are the lengths of the parallel sides and $h$ is the height.

The parallel sides are the time intervals where the velocity is non-zero.
Length of the top parallel side (constant velocity section): $40 \text{ s} - 20 \text{ s} = 20 \text{ s}$.
Length of the bottom parallel side (total time): $50 \text{ s} - 0 \text{ s} = 50 \text{ s}$.
The height of the trapezoid (maximum velocity) is 30 m/s.

The total distance travelled is $\boxed{\text{1050 m}}$.