Question

The following graph shows the change of a car's speed with time. How far did the car travel (in $\text{m}$) before it reached a constant speed?

• A. 100

Answer 1

The correct option is A 100
From the given graph:
The slope is increasing from time, ${\text{t}}_1=0\text{s}$ to ${\text{t}}_2=10\text{s}$.
In this time interval, the speed has increased from ${\text{v}}_1=0{\text{m s}}^{-1}$ to ${\text{v}}_2=20{\text{m s}}^{-1}$.

The distance travelled by the car before it reaches a constant speed $=$ Area of the triangle = $\frac{1}{2}\times 20\times 10$

$10{\text{m s}}^{-1}\times 10\text{s}=100\text{m}$