What is the formula for potassium hydroxide? KOH K2O PtOH (Pt)2O

At what height must a 6-kilogram object be placed to have 12 joules of

Serga [27]

Answer:

0.2m

Explanation:

Using E=mgh

12=6*9.8*h

h=0.2m (1 d.p.)

4 0

4 years ago

The mass of a glass beaker is known to be 24.2 g. Approximately 5 mL of water are added, and the mass of the beaker and water is

Kamila [148]

Answer: 2 significant figures in 6.4

Explanation:

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

Rules for significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant figures.

All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.

All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.

All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.

All zero’s after the decimal point are always significant. For example: 4.500, 45.00 and 450.0 all have four significant figures.

Mass of beaker = 24.2 g

Mass of beaker + mass of water = 30.625 g

Mass of water = 30.625 - Mass of beaker = 30.625 - 24.2 = 6.4g

The rule apply for the addition and subtraction is :

The answer would contain same number of decimal places as there are in the least precise number present.

Thus there are 2 significant figures in mass of water which is 6.4 grams.

7 0

3 years ago

A bike race against the clock takes place on a straight road. Yan drives at 37 km / h and he starts the course 30s before Christ

joja [24]

Given data:

Yan speed;

$u_1=37\text{ km/h}$

Christopher speed;

$u_2=38.9\text{ km/h}$

Christophe starts 30 s later than Yan. Therefore, Christophe takes 30 s less than Yan to reach the same distance.

Part (A)

The distance is given as,

$d=ut$

Let both Yan and Christophe meet at d distance from the start position. Therefore,

$u_1t=u_2(t-30)$

Substituting all known values,

$\begin{gathered} (37\text{ km/h})t=(38.9\text{ km/h})\times(t-30) \\ \frac{(37\text{ km/h})}{(38.9\text{ km/h})}=\frac{(t-30)}{t} \\ 0.95=1-\frac{30}{t} \\ \frac{30}{t}=1-0.95 \\ \frac{30}{t}=0.05 \\ t=\frac{30}{0.05} \\ t=600\text{ s} \end{gathered}$

Therefore, 600 s after Yan's departure Christophe will join him.

Part (B)

The distance is given as,

$d=u_1t$

Substituting all known values,

$\begin{gathered} d=(37\text{ km/h})\times(600\text{ s}) \\ =(37\text{ km/h})\times(600\text{ s})\times(\frac{1\text{ hr}}{3600\text{ s}}) \\ \approx6.17\text{ km} \end{gathered}$

Therefore, Christophe joins Yan after 6.17 km from the start.

3 0

1 year ago

HELP ME PLEASE AND HURRY !!!!!!

hodyreva [135]

Answer:

mass number = protons + neutrons

8 0

2 years ago

Read 2 more answers

If you were to make a three-dimensional model of magnetic force using a magnet and magnetic field lines, which two characteristi

kkurt [141]

Answer:

- the Magnetic field lines will spread out of the north end of the magnet.

- the magnetic fields will three-dimensional and resemble a bubble.

Explanation:

- Usually, when drawing magnetic field lines, we start outwardly from the North pole to the South Pole. This same direction is also prevalent on the Earth due to the fact that the Earth functions as a giant magnet. Thus, one characteristic of the model is that the Magnetic field lines will spread out of the north end of the magnet.

- Another thing is that Magnetic field forces are usually driven as a result bubble like configuration which affects the objects that are in such a configuration. Thus, another characteristic of the model is that the magnetic fields will three-dimensional and resemble a bubble.

8 0

3 years ago