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3 years ago

What two terms best describe the variable "air pressure inside the football" in this experiment?

Physics

1 answer:

jeka57 [31]3 years ago

7 0

Answer:

one of them is the answer

Explanation:

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When radioactive tracers are used for medical scans, the tracers both decay in the body via radiation, as well as being excreted

irinina [24]

Answer:

Effective half-time of the tracer is 3.6 days

Explanation:

The formula for calculating the decay due to excretion for the first process is ;

$\frac{dN_1}{dt } = - \lambda _e N_o$

here ;

$N_o$ = initial number of tracers

Then to the second process ; we have :

$\frac{dN_2}{dt } = - \lambda _e N_o$

The total decay is as a result of the overall process occurring ; we have :

$\frac{dN_{total}}{dt } = \frac{dN_1}{dt} + \frac{dN_2}{dt}$ ------ (1)

here ;

$\frac{dN_{total}}{dt } = \lambda _{total} N_o$

Putting the values in (1);we have :

$- \lambda _{Total} N_o = - \lambda_e N_o + ( -\lambda r N_o})$

$\lambda _{Total} = \lambda_e + \lambda r$

As we also know that:

$\frac{1}{t_{1/2}} = \frac{[t_{1/2}]_{radiation}+[t_{1/2}]_{excretion}}{[t_{1/2}]_{radiation}*[t_{1/2}]_{excretion}}$

$\frac{1}{t_{1/2}}_{effective}} = \frac{[t_{1/2}]_{radiation}+[t_{1/2}]_{excretion}}{[t_{1/2}]_{radiation}*[t_{1/2}]_{excretion}}$

$\frac{1}{t_{1/2}}_{effective}} = \frac{9+6}{9*6}$

$\frac{1}{t_{1/2}_{effective}}}=\frac{15}{54}$

$t_{1/2}_{effective}} = \frac{54}{15}$

= 3.6 days

5 0

4 years ago

Read 2 more answers

Which describes an object’s speed in free fall?

Mrac [35]

"Free fall" is the motion of an object when gravity is the ONLY force
acting on it.

In true 'free fall' the speed of an object increases at a constant rate
for the total duration of the fall. The rate of increase, on or near the
Earth's surface, is 9.8 meters per second for each second of fall.

True free fall is almost impossible to observe in everyday life, because
whenever we see anything falling, it's almost always falling through air,
so gravity is NOT the only force acting on it. The friction due to the
motion through air works against the gravitational force. In many cases,
the result is that the object's speed eventually stops increasing and
becomes constant, at a speed often described with the faux technical,
high-fallutin' sounding phrase "terminal velocity". It must be understood
that 'terminal velocity' is NOT a property of gravity or of free fall, but is
only a result of falling through some surrounding stuff that interferes with
the process of true 'free fall'.

6 0

4 years ago

Read 2 more answers

An aluminum sphere is 8.55 cm in diameter. What will be it's % change in volume if it is heated from 30 C to 155 C?

Ghella [55]

We know that

• The sphere diameter is 8.55 cm.

• The temperature change is from 30 C to 155 C.

First, we have to find the radius of the sphere. The radius is the half diameter.

$\begin{gathered} r=\frac{d}{2}=\frac{8.55\operatorname{cm}}{2} \\ r=4.275\operatorname{cm} \end{gathered}$

Now we have to find the volume of the sphere using the following formula.

$V=\frac{4}{3}\pi(r)^3$

Where r = 4.275 cm.

$\begin{gathered} V=\frac{4}{3}\pi(4.275\operatorname{cm})^3 \\ V\approx327.26(cm)^3 \end{gathered}$

Then, we use the following formula

$V_2-V_1=BV_0(T_2-T_1)$

Where the initial volume is 327.26 cubic cm, B is a constant about thermal expansion for aluminum, and we have to find the final volume to then calculate the percentage change.

$\begin{gathered} \Delta V=75\times10^{-6}\cdot327.26(155-30) \\ \Delta V=75\times10^{-6}\cdot327.26(125) \\ \Delta V\approx3.07(cm)^3 \end{gathered}$

This means that the volume change is 3.07 cubic centimeters.

At last, we have to divide the volume change by the initial volume, and then we have to multiply it by 100% to express it as a percentage.

$\frac{\Delta V}{V_1}\times100=\frac{3.07}{327.26}\times100\approx0.938$ <h2>Therefore, the percentage change is 0.938%.</h2>

5 0

1 year ago

This is the sum of all the forces applied to an object. It is usually separated into a horizontal and vertical component.

evablogger [386]

Answer: Net Force, also is referred to as Resultant Force

5 0

3 years ago

Read 2 more answers

A+car+accidently+rolls+off+a+cliff.As+it+leaves+the+cliff+it+has+a+horizontal+velocity+of+13+m/s,it+hits+the+ground+60m+from+the

erastovalidia [21]

Answer:

104.6 m

Explanation:

The motion of the car is a projectile motion, consisting of:

- A horizontal motion at constant speed

- A vertical motion at constant acceleration (acceleration of gravity)

We know that:

The initial horizontal velocity of the car is $v_x = 13 m/s$ , and this is constant during the entire motion, as there are no forces in the horizontal direction