Asmall block of mass 0.91 kg slides without friction on a horizontal table. initially it moves in a circle of radius r0 = 0.63 m with a speed 1.5 m/s. it is held in its path by a string that passes through a small hole at the center of the circle. the string is then pulled down a distance of r0 - r1 = 0.12 m, leaving it at a radius of r1 = 0.51 m. it is pulled so slowly that the object continues to move in a circle of continually decreasing radius. how much work was done by the force to change the radius from 0.63 m to 0.51 m? w =

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.