Exercise 1.
the stone is falling from a height of h = 1200 m. what path s will the stone go in the last second of its falling?
exercise 2.
the movement of a point along a circle with a radius of r = 4 m is given by the equation = a +bt + ct 2, where a = 10 m, b = -2 m/s, c = 1 m/s. find the tangential at, normal an and the full
a acceleration of the point at time t = 2 s.
exercise 3. determine the period t, the frequency v, and the initial phase o of the oscillations
given by law of oscillatory motion x = a sin ш (t+т), where ш = 2.51 пs-1, т= 0.4 s.
exercise 4. the law of oscillatory motion is expressed x = a cos шt, where a = 5 cm; ш = 2 s-1.
determine the acceleration | a | at a time when its velocity was v = 8 cm/s.
U1 (5/t) t = U2 (10/t) t
5 U1 = 10 U2
U1 = 2 U2
Напряжение на первом участке вдвое больше, чем на втором.
2. Мощность электродвигателя P = UI = 220 В * 10 А = 2200 Вт. Значит в час он потребляет 2200 * 3600 = 7920000 Вт*ч = 7920 кВт*ч.
Общее время его работы t = 30 * 8 = 240 ч (не будем переводить в секунды). Значит общее потребление Q = Pt = 7920 * 240 = 1900800 кВт*ч.