A weight of 4 N is suspended from a string. The thread with the weight is lowered with an acceleration

A weight of 4 N is suspended from a string. The thread with the weight is lowered with an acceleration of 5 m / s2. What is the thread tension?

P = 4 N.

a = 5 m / s2.

N -?

When lowering the load, 2 forces act on it: the force of gravity Ft directed vertically downward, the tension force of the thread N directed vertically upward.

m * a = m * g + N – 2 Newton’s law in vector form.

For projections onto a vertical axis directed vertically upward, 2 Newton’s law will take the form: – m * a = – Fт + N.

N = Fт – m * a.

In a state of rest or uniform rectilinear motion, the force of gravity Ft is equal to the weight of the body P: Ft = P.

The force of gravity is determined by the formula: Ft = m * g.

P = m * g.

N = P – P * a / g.

N = 4 N – 4 N * 5 m / s2 / 10 m / s2 = 2 N.

Answer: when lowering the load with acceleration, the tension force of the thread will be N = 2 N.