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Flura [38]
3 years ago
9

Alexandra knows that the atomic number of the element potassium, K, is 19. She also knows that one particular isotope of potassi

um has a mass number of 39. How many neutrons can be found in the nucleus of this isotope of potassium?
A) 19

B) 20

C) 39

D) 58
Physics
1 answer:
fiasKO [112]3 years ago
8 0
I believe the answer is 58 but I’m not sure
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2. What is the water pressure at a depth of 24 m in a lake? [Density of water, p = 1 000 kg m- and gravitational acceleration, g
Andrei [34K]

Answer:

Pressure = ρgh

pressure (p) is measured in pascals (Pa)

density (ρ) is measured in kilograms per metre cubed (kg/m3)

The fore of gravitational field strength (g) is measured in N/kg or m/s 2

height of column (h) is measured in metres (m)

Answer = 235,200 Pa

Explanation:

Pressure = ρgh

Pressure = 1,000 x 9.8 x 24

Pressure = 235,200 Pa

4 0
2 years ago
Negative charges can move from one insulator to another.<br> True<br> False
Rasek [7]

Answer:

True

Explanation:

Because in atom the negative charge become lose or gain.

6 0
3 years ago
A small block with mass 0.0400 kg is moving in the xy-plane. The net force on the block is described by the potentialenergy func
OlgaM077 [116]

Answer:

A= 148.92  m/s²

Explanation:

Given that

U(x,y) = (6.00  )x²  - (3.75  )y ³

m= 0.04 kg

Now force in the x-direction

Fx= - dU/dx

U(x,y) = (6.00  )x²  - (3.75  )y ³

dU/dx= 12 x

When x=0.4 m

dU/dx= 12 x 0.4 = 4.8

So we can say that

Fx= - 4.8 N

From Newtons law

F= m a

- 4.8 = 0.04 x a

a = -120 m/s²

Acceleration in x direction ,a = -120 m/s²

In y -direction

F= - dU/dy

U(x,y) = (6.00  )x²  - (3.75  )y ³

dU/dy = 0 - 3.75 x 3 y²

When y = 0.56 m

dU/dy = - 3.75 x 3 x 0.56 x 0.56

dU/dy = - 3.52

So we can say that force in y -direction

F= 3.52 N

F= m a'

3.52 = 0.04 x a'

a'=88.2 m/s²

acceleration in y direction is 88.2 m/s²

The resultant acceleration

A=\sqrt{a^2+a'^2}

A=\sqrt{120^2+88.2^2}

A= 148.92  m/s²

7 0
3 years ago
The speed of a moving bullet can be deter-
Bad White [126]

Answer:

<em>v = 381 m/s</em>

Explanation:

<u>Linear Speed</u>

The linear speed of the bullet is calculated by the formula:

\displaystyle v=\frac{x}{t}

Where:

x = Distance traveled

t = Time needed to travel x

We are given the distance the bullet travels x=61 cm = 0.61 m. We need to determine the time the bullet took to make the holes between the two disks.

The formula for the angular speed of a rotating object is:

\displaystyle \omega=\frac{\theta}{t}

Where θ is the angular displacement and t is the time. Solving for t:

\displaystyle t=\frac{\theta}{\omega}

The angular displacement is θ=14°. Converting to radians:

\theta=14*\pi/180=0.2443\ rad

The angular speed is w=1436 rev/min. Converting to rad/s:

\omega = 1436*2\pi/60=150.3776\ rad/s

Thus the time is:

\displaystyle t=\frac{0.2443\ rad}{150.3776\ rad/s}

t = 0.0016 s

Thus the speed of the bullet is:

\displaystyle v=\frac{0.61}{0.0016}

v = 381 m/s

7 0
3 years ago
David is driving a steady 30 m/s when he passes Tina, who is sitting in her car at rest. Tina begins to accelerate at a steady 2
dangina [55]
A. 441 m B: 46.0 m/s
5 0
2 years ago
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