An automobile and a truck start from rest at the same instant, with the automobile initially at some distance behind the truck. The truck has a constant acceleration of 2.10 m/s2, and the automobile an acceleration of 3.40 m/s2. The automobile
overtakes the truck after the truck has moved 40.0 m. (a) How much time does it take the automobile to overtake the truck? (b)
How far was the automobile behind the truck initially? (c) What is the speed of each when they are abreast? (d) On a
single graph, sketch the position of each vehicle as a function of time. Take x = 0 at the initial location of the truck.

a and b sometimes have a positive value

i believe the answer is a hope it and is correct

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).