What are the 2 forms of memory retrieval?

3. Sodium-24 has a half-life of 15 hours. If a sample of sodium-24 has an

sattari [20]

Answer:

See explanation

Explanation:

From the formula;

0.693/t1/2 = 2.303/t log (Ao/A)

t1/2 = half life of Sodium-24

Ao = initial activity of Sodium-24

A= activity of Sodium-24 at time = t

So,

0.693/15 = 2.303/15 log (800/A)

0.0462 = 0.1535 log (800/A)

0.0462/0.1535 = log (800/A)

0.3 = log (800/A)

Antilog(0.3) = (800/A)

1.995 = (800/A)

A = 800/1.995

A = 401 Bq

ii) 0.693/15 = 2.303/30 log (800/A)

0.0462 = 0.0768 log (800/A)

0.0462/0.0768 = log (800/A)

0.6 = log (800/A)

Antilog (0.6) = (800/A)

3.98 = (800/A)

A = 800/3.98

A = 201 Bq

iii)

0.693/15 = 2.303/45 log (800/A)

0.0462 = 0.0512 log (800/A)

0.0462/0.0512 = log (800/A)

0.9 = log (800/A)

Antilog (0.9) = (800/A)

7.94 = (800/A)

A = 800/7.94

A= 100.8 Bq

iv)

0.693/15 = 2.303/60 log (800/A)

0.0462 = 0.038 log (800/A)

0.0462/0.038 = log (800/A)

1.216 = log (800/A)

Antilog(1.216) = (800/A)

16.44 = (800/A)

A = 800/16.44

A = 48.66 Bq

3 0

3 years ago

A water pipe tapers down from an initial radius of R1 = 0.21 m to a final radius of R2 = 0.11 m. The water flows at a velocity v

Aleks [24]

Answer:

$0.116 m^3/s$

Explanation:

The volume flow rate of a fluid in a pipe is given by:

$Q=Av$

where

A is the cross-sectional area of the pipe

v is the speed of the fluid

In this problem, at the initial point we have

v = 0.84 m/s is the speed of the water

r = 0.21 m is the radius of the pipe, so the cross-sectional area is

$A=\pi r^2 = \pi (0.21 m)^2 =0.138 m^2$

So, the volume flow rate is

$Q=(0.138 m^2)(0.84 m/s)=0.116 m^3/s$

8 0

3 years ago

What is the best way to avoid being run over by your own pwc or motorboat?

kobusy [5.1K]

Wear an ignition safety switch lanyard so you can turn it off. Most powerboats and PWCs come furnished by the maker with a crisis motor cut-off switch. This wellbeing gadget can stop the motor if the administrator tumbles off the PWC or out of the powerboat, or is generally tossed from the best possible working position.

5 0

3 years ago

A Venturi tube may be used as a fluid flowmeter. Suppose the device is used at a service station to measure the flow rate of gas

leonid [27]

Answer

given,

flow rate = p = 660 kg/m³

outer radius = 2.8 cm

P₁ - P₂ = 1.20 k Pa

inlet radius = 1.40 cm

using continuity equation

A₁ v₁ = A₂ v₂

π r₁² v₁ = π r₁² v₂

$v_1= \dfrac{r_1^2}{r_2^2} v_2$

$v_1= \dfrac{1.4^2}{2.8^2} v_2$

$v_1= 0.25 v_2$

Applying Bernoulli's equation

$\Delta P = \dfrac{1}{2}\rho (v_2^2-v_1^2)$

$\Delta P = \dfrac{1}{2}\rho (v_2^2-(0.25 v_2)^2)$

$\Delta P = \dfrac{1}{2}\rho v_2^2 (1 - 0.0625)$

$v_2=\sqrt{\dfrac{2\Delta P}{\rho(1 - 0.0625)}}$

$v_2=\sqrt{\dfrac{2\times 1200}{660 \times(1 - 0.0625)}}$

v₂ = 1.97 m/s

b) fluid flow rate

Q = A₂ V₂

Q = π (0.014)² x 1.97

Q = 1.21 x 10⁻³ m³/s

5 0

3 years ago

A pendulum has 711 J of potential energy at the highest point of its swing. How much kinetic energy will it have at the bottom o

Anika [276]

According to law of conservation of energy,
Energy can neither be constructed nor be destroyed but can be transformed from one form to another.

At the highest point of the pendulum(point b), pendulum is associated with potential energy only and no kinetic energy.
Therefore total energy at point b = potential energy = 711 J.... i

At the bottom most point(point a), pendulum is associated only with kinetic energy and no potential energy.
Therefore total energy at point a = kinetic energy ---- ii
From i and ii,
Kinetic energy = potential energy = 711 J.(Conserving energy)

Hence kinetic energy at the bottom most point is 711 J.
Hope this helps!!

7 0

3 years ago