Afullback having a mass of 9.0x10^1 kg is running at 4.5 m/s [e]. he is hit by a linebacker and 1.2 s later is moving backwards at 1.5 m/s [w].find:
a) the impulse imparted to the fullback b) the average force exerted on the fullback by the linebacker
my work: impulse is p so p= p2-p2 p=m2v2-m1v1 but its all wrong because the answer is 5.4 x 10^2 kg. m/s [w] apparently. !

the answer is false

explanation:

statement #3 on andre"s list is false.

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.