Race cars A and B are driving on the same circular racetrack at the same speed of 45.0 m/s. At a given instant car A is on the north side of the track moving eastward and car B is on the south side of the track moving westward. Find the magnitude of the velocity vector of car A relative to car B.

90 m/s

Explanation:

Given

Speed of both the car is

Suppose North side and East side as Positive Y and x axis

so Velocity of car A can be written as

Velocity of car B is

Velocity of car A relative to car B is given by

Magnitude of velocity is

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.

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.