According to Newtons second law of motion:
[tex]a = \frac{F}{m} [/tex]
This shows, acceleration and mass are inversely proportional. So, larger the mass, less will be the acceleration produced and vice versa.
In case of a sports car and a fully loaded truck, the mass of truck is a lot more than the sports car. As a result the sports car will accelerate faster when the traffic light turns green.
