I pull my child in a sled over the snow. The rope makes an angle with the horizontal so that the pulling force has a horizontal component of 16 N and a vertical component in the upwards direction 25 N . The combined weight of the child and sled is 84 N . I'm getting tired and so the sled is slowing at a constant rate of 0.80 m/s each second. Calculate the magnitude of the frictional force between the sled and the snow.

f is prop to m1xm2 double m1 double force

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.