Trong không gian với hệ tọa độ Oxyz, cho hai vectơ

You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. Y

Troyanec [42]

Staals half
1 gram left
0.3 grams left
half lives are normally written in years
it goes likt this

$A=P( \frac{1}{2})^ \frac{t}{h}$
A=final amount
P=initila amount
t=time elapsed
h=time half life is (same units as time)

let's use days as the units of time

we are given
initial amount=1gram
final amount=0.3gram
time=4 days

so
$0.3=1( \frac{1}{2})^ \frac{4}{h}$
solve for h
$0.3=( \frac{1}{2})^ \frac{4}{h}$
take the ln of both sides
$ln(0.3)=ln( \frac{1}{2})^ \frac{4}{h}$
$ln(0.3)=\frac{4}{h}ln( \frac{1}{2})$
times both sides by h
$hln(0.3)=4ln( \frac{1}{2})$
divide both sides by ln(0.3)
$h= \frac{4ln( \frac{1}{2}) }{ln(0.3)}$
use calculator
h=2.30287
3 sig figs
h=2.303 days

6 0

3 years ago

A man is standing at a radar base and observes an unidentified plane at an altitude 6000m flying towards the radar base at an an

liubo4ka [24]

Answer:

The speed in of the plane is 115.47 m/sec

Step-by-step explanation:

Given:

Height at which the plane is flying = 6000 m

Angle of elevation at the radar base = 30 Degrees

Angle of elevation at the radar base after one minute = 60 Degrees

To Find:

The Speed of the plane in meter per second = ?

Solution:

Let us use the tangent of the angle to find the distance (d) to a point directly below plane:

when the angle is 30 degrees

$tan(30) = \frac{6000}{d1}$

$d1 = \frac{6000}{tan(30)}$

$d1 = \frac{6000}{0.577}$

d1 = 10392.3 meters

when the angle is 60 degrees

$tan(60) = \frac{6000}{d2}$

$d2 = \frac{6000}{tan(60)}$

$d2 = \frac{6000}{1.732}\\$

d2 = 3464.1 meters

distance travelled by aircraft in 1 min is

=>d1 - d2

=>0392.3 - 3464.1

= 6928.2 m/min

Now converting to m/sec

=> $\frac{6928.2}{60}$

=>115.47 m/sec

4 0

3 years ago

Find the angles of x and y

Gnesinka [82]

or, x=180

or,34=180

or,180-34

or x=146

Now,

or, y=146

or,18=146

or146-18

or, y=128

there is x is 34 and its all side angle is 180 degree So put x =180 and then put x value is 34 =180 and there is no values in front of 34 so there will be + and if +so in another side it will be - and then after put 180-34=146

5 0

3 years ago

Which of the following inequalities have -8 in its solution set?

BaLLatris [955]

Answer:

3x >/= 24 or 3x </= -24

Step-by-step explanation:

Plug in (-8) for (x) and solve.

8 0

3 years ago

If <img src="https://tex.z-dn.net/?f=36%20%5E%7B12%20-%20m%7D%20%3D%206%5E%7B2m%7D%20" id="TexFormula1" title="36 ^{12 - m}

Katyanochek1 [597]

Answer:

6

Step-by-step explanation:

$6^{2(12-m)}=6^{2m}\\2(12-m)=2m\\24-2m=2m\\24=4m\\m = 6$

8 0

2 years ago