The alarm at a fire station rings and a 84.5-kg fireman, starting from rest, slides down a pole to the floor below (a distance of 4.47 m). just before landing, his speed is 1.49 m/s. what is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole?

Explanation:

As we know that fireman starts from rest

so here we have

now we can use kinematics to find the acceleration

as we know by force equation

u=13

v=30

s/t=u+1\2at

=13+431/2

=13+265.5

=278.5

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.