7. A volcanic island arc is formed when

A patient is administered 20 mg of iodine-131. How much of this isotope will remain in the body after 40 days if the half-life f

igor_vitrenko [27]

The formula for half-life is:

$A_{final}=A_{initial}(\frac{1}{2})^{\frac{t}{h}}$

Where A is the amount of iodine-131 initially and after 40 days, t is time, h is half-life of the isotope. Let's plug in our values to the equation:

$A_{final}=20(\frac{1}{2})^{\frac{40}{8}=0.625g$

Therefore, the patient has 0.625 grams of iodine-131 after 40 days.

4 0

3 years ago

The temperature of the cosmic background radiation is measured to be 2.7 k. What is the wavelength of the peak in the spectral d

KATRIN_1 [288]

Answer:

$1.07\cdot 10^{-3} m$

Explanation:

The peak wavelength of the spectral distribution can be found by using Wien's displacement law:

$\lambda=\frac{b}{T}$

where

$b=2.898\cdot 10^{-3} m\cdot K$ is Wien's displacement constant

T is the absolute temperature

For the cosmic background radiation, the temperature is

T = 2.7 K

So, the corresponding peak wavelength is

$\lambda=\frac{2.898\cdot 10^{-3} m\cdot K}{2.7 K}=1.07\cdot 10^{-3} m$

7 0

3 years ago

Two forces of magnitudes 4.0 Newtons and 3.0 Newtons pull on a box. The forces make an angle of 40° with each other. What is the

leonid [27]

Answer:

6.6 N

Explanation:

Let's take the direction of the force of 4.0 N as positive x-direction. This means that the force of 3.0 N is at 40 degrees above it. So the components of the two forces along the x- and y-directions are:

$F_{1x} = 4.0 N\\F_{1y} = 0$

$F_{2x} = 3.0 N cos 40^{\circ}=2.3 N\\F_{2y} = 3.0 N sin 40^{\circ} = 1.9 N$

So the resultant has components

$F_x = F_{1x}+F_{2x}=4.0 N +2.3 N = 6.3 N\\F_y = F_{1y} + F_{2y} = 0 + 1.9 N = 1.9 N$

So the magnitude of the resultant is

$F=\sqrt{F_x^2 +F_y^2}=\sqrt{(6.3)^2+(1.9)^2}=6.6 N$

And in order for the body to be balanced, the third force must be equal and opposite (in direction) to this force: so, the magnitude of the third force must be 6.6 N.

3 0

3 years ago

An electric field around two charged objects is shown.

mamaluj [8]

Answer: D

<u></u>

X: positive

Y: negative

Explanation:

It's either A or D and I chose A and got it wrong.

3 0

3 years ago

A car is being driven at a rate of 60 ft/sec when the brakes are applied. The car decelerates at a constant rate of 19

Hunter-Best [27]

The car will take 300 m before it stops due to applying break.

<h3>What's the relation between initial velocity, final velocity, acceleration and distance?</h3>

As per Newton's equation of motion, V² - U² = 2aS
V= final velocity velocity of the object, U = initial velocity velocity of the object, a= acceleration, S = distance covered by the object
Here, U = 60 ft/sec, V = 0 m/s, a= -6 ft/sec²
So, 0² - 60² = 2×6× S

=> -3600 = -12S

=> S = 3600/12 = 300 m

Thus, we can conclude that the distance covered by the car is 300 m before it stopped.

Disclaimer: The question was given incomplete on the portal. Here is the complete question.

Question: A car is being driven at a rate of 60 ft/sec when the brakes are applied. The car decelerates at a constant rate of 6 ft/sec². How long will it take before the car stops?

Learn more about the Newton's equation of motion here:

brainly.com/question/8898885

#SPJ1

7 0

2 years ago