With what force does the load press on the bottom of the lift, on which the force of gravity 980N acts

With what force does the load press on the bottom of the lift, on which the force of gravity 980N acts, if the lift moves with acceleration of 0.245m / s2 directed upward? Directed downward? Does the pressure force depend on the direction of movement? free falling elevator?

Ft = 980 N.

g = 9.8 m / s2.

a = 0.245 m / s2.

P -?

The force with which the load presses on the floor is called the body weight R.

Two forces act on the load: gravity Ft directed vertically downward, force N, with which the floor presses on the load, directed vertically upward.

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

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

N = m * a + Fт.

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

m = Fт / g.

N = a * Ft / g + Ft.

According to Newton’s 3 laws, the force N with which the floor presses on the load is equal to the force P with which the load presses on the floor P: N = P.

P = a * Ft / g + Ft.

P = 0.245 m / s2 * 980 N / 9.8 m / s2 + 980 N = 1004.5 N.

With the direction of acceleration a downward: – m * a = – Ft + N.

N = Ft – m * a = Ft – a * Ft / g.

P = Ft – a * Ft / g.

P = 980 N – 0.245 m / s2 * 980 N / 9.8 m / s2 = 955.5 N.

In a freely falling elevator, the load will be from zero gravity, therefore P = 0 N.

Answer: with acceleration directed upwards P = 1004.5 N, acceleration directed downward P = 955.5 N.



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