A50 kg box hangs from a rope. what is the tension in the rope if the box moves up at a steady 5.0 m/s

There are two forces acting on the box: the tension of the rope (upward) and the weight (downward). The problem says the box moves up at constant speed: this means that its acceleration is zero, therefore for Newton's second law, the resultant of the forces acting on the box is zero. This implies that the tension of the rope is equal to the weight of the box, which is:

coil wire, increase current, put iron inside the coil

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.