How to calculate the ratio (1) 35:105 (2) 1 / 2: 7 (3) 3:0.25 (4) 0.72:0.36 (5) 5 / 6: 2 / 3 (6) 5 / 4: 9 / 8 (7) 0.3:2

How to calculate the ratio (1) 35:105 (2) 1 / 2: 7 (3) 3:0.25 (4) 0.72:0.36 (5) 5 / 6: 2 / 3 (6) 5 / 4: 9 / 8 (7) 0.3:2

Divide the first by the second. The ratio is the formula of division

(- 7 / 4) - (- 1 / 3) - (+ 2 / 9) + (- 1 / 6)

(- 7 / 4) - (- 1 / 3) - (+ 2 / 9) + (- 1 / 6)
=(- 4.9-7.2-9.2) + (3.6-6.6)
=-7-3
=-10

(- 4 and 9 / 7) - (- 3 and 6 / 1) - (+ 2 and 9 / 2) + (- 6 and 6 / 1) are calculated by rational number addition law

(- 7 / 4) - (- 1 / 3) - (+ 2 / 9) + (- 1 / 6)
=(- four and seven ninths) - two and two ninths - (- three and one sixth) + (- six and one sixth)
=-7-3
=-10

2013 eighth grade summer homework relay press, not 2012, not the same
Science in 2012 and 2013 is different. That is, 35 pages later is different. Just give science

I'll give you a question and I'll do it for you~

In order to adjust the speed of DC motor, a variable resistor is often connected in series. In the circuit diagram, M is a small DC motor, which is marked with "12V, 24W", and the power supply voltage is 20V. When the motor works normally, (1) what is the resistance value of the variable resistor? (2) What is the total power supplied by the power supply and the power consumed by the variable resistor?

According to the circuit diagram, the motor and the sliding rheostat are connected in series, and the voltmeter measures the voltage at both ends of the sliding rheostat. (1) when the motor works normally, the voltage is 12V, the power is 24W, ∵ the current in the series circuit is equal, ∵ according to p = UI, the current in the circuit: I = pmum = 24w12v = 2A, ∵ the series circuit

Simple calculation of 237 × 99 plus 237

237×99+237
=237×(99+1)
=237×100
=23700

How do batteries convert chemical energy into electrical energy?

In fact, a battery consists of two metals with different chemical properties (one of which can be a carbon rod) in a solution (electrolyte solution. Not ordinary water). In the redox reaction, electrons are transferred, thus generating an electric current. Electrons are lost on the active metal, When consumed to a certain extent, the anode materials or electrolytes have little or no reaction, which means that there is no current ~ the charging of rechargeable battery is the reverse reflection of this, which is called electrolysis cell ~ don't worry, high school~

What is (x + 600) × 95% = 480 + 80% (x + 600)

0.95(x+600)=480+0.8(x+600)
0.95(x+600)-0.8(x+600)=480
0.15(x+600)=480
x+600=480÷0.15=3200
x=3200-600
x=2600

Fruit batteries convert bioenergy into electricity, right

Yes, chemical energy is converted into electric energy ~ ~ ~ the power generation principle of fruit battery is: the electrochemical activity of two kinds of metal sheet is different, and the more active metal sheet can replace the hydrogen ion of acid substance in fruit. Due to the positive charge, the whole system needs to be stable (or generate electric field, electric field

How to live in space

There is no gravity in space. Everything floats. Food should be squeezed into your mouth like toothpaste. People should be fixed with cables,