A math problem, ten minutes to answer plus 10 points Put 15kg milk into three equal weight barrels. The first barrel weighs 13kg, the second barrel weighs 23kg, and the third barrel contains 1 / 2 of all milk. How many kg does each empty barrel weigh?

A math problem, ten minutes to answer plus 10 points Put 15kg milk into three equal weight barrels. The first barrel weighs 13kg, the second barrel weighs 23kg, and the third barrel contains 1 / 2 of all milk. How many kg does each empty barrel weigh?

15/2=7.5
13/4+23/4=9
9-7.5=1.5
1.5/2 = 0.75kg

A 168 cm long iron wire is welded into a rectangular model with the ratio of length, width and height of 3:2:1. How many cm are the length, width and height of the model?

3 + 2 + 1 = 6168 △ 4 = 42 (CM), 42 × 36 = 21 (CM), 42 × 26 = 14 (CM), 42-21-14 = 7 (CM). A: the length, width and height of this model are 21 cm, 14 cm and 7 cm respectively

A 168 cm iron wire is welded into a cuboid model. It is required that all the iron wires are used up and the ratio of length to width to height is 6:5:3?

168 △ 4 = 42 cm
42 ÷ (6 + 5 + 3) = 3cm
3 × 6 = 18 cm
3 × 5 = 15 cm
3 × 3 = 9 cm
A: length, width and height are 18 cm, 15 cm and 9 cm respectively

A 168 cm iron wire is welded into a rectangular model with the ratio of length, width and height of 3:2:1. How many centimeters are the length, width and height?

Length: 168 ／ 4 ／ (3 + 2 + 1) × 3 = 21 cm
Width: 168 ／ 4 ／ (3 + 2 + 1) × 2 = 14 cm
Height: 168 ／ 4 ／ (3 + 2 + 1) × 1 = 7 cm

When a 4.8m long iron wire is used to form a cuboid, the ratio of length to width to height is 3:2:1
Use a long one
The ratio of length to width is 3:2:1 when 4.8m iron wire is used to form a cuboid. How many cubic meters is the cuboid?
20 out of 13 minus (4 out of 5 + 7 out of 13)
fast

Length + width + height = 4.8 △ 4 = 1.2m;
Length = 1.2 × 3 ^ (3 + 2 + 1) = 0.6m;
Width = 1.2 × 2 ÷ (3 + 2 + 1) = 0.4m;
Height = 1.2-0.6-0.4 = 0.2m;
Volume = 0.6 × 0.4 × 0.2 = 0.048 m3;
20/13-(4/5+7/13)
=(20-7)/13-4/5
=1-4/5
=1/5;
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What does min mean in physics

Minutes

What does rad mean in physics

The unit of radian, 2 π rad = 360 ° rad is often used to form the unit of angular velocity with S

The speed of the electric fan in a certain gear is n = 60 π rad / min, and the angular velocity of the blade in normal rotation is ω=_______ rad/s.

ω=60π/60=πrad/s.

How to convert the unit of angular velocity R / min into rad / S

The radius of the wheel is 1.2m, the speed is 12m / s, and the angular speed of the wheel is 1.2m______ Rad / s, its period is______ s．

From the formula of linear velocity and angular velocity v = ω R, we get: ω = VR = 12m / s1.2m = 10s-1 = 10rad / S; from ω = 2 π T, we get t = 2 π ω = 2 π rad10rad / S = 0.2 π s; so the answer is: 10, 0.2 π