All categories

3 years ago

An atom of potassium has an atomic mass of 39 amu and an atomic number of 19. It therefore has ______ neutrons in its nucleus.

Physics

2 answers:

Sedbober [7]3 years ago

8 0

mera verga pijaaaaaaaaaaaa

FromTheMoon [43]3 years ago

6 0

A=atomic mass
Z=atomic number (nº of protons).
N=neutons.

A=Z+N

Data:
A=39
Z=19

A=Z+N
39=19+N
N=39-19=20.

It therefore has 20 neutrons in its nucleus.

You might be interested in

A car starts from a stopped position at a red light. At the end of 30 seconds, its speed is 20 meters per second. What is the ac

Gnoma [55]

A=deltav/t
Vf=20m/s
Vi=0m/s
(20-0)/30
=0.667 m/s^2

5 0

3 years ago

How do Swati and Banks adjust their body position during a skydiving jump so they can fall at the same rate?

vlada-n [284]

when skydiving, its not just freely falling under Earth's gravity. Additional force called drag acts against the gravity which slows down the rate of fall. Drag is caused by the air molecules which push against the body as it falls through them. This is actually a significant amount of force which slows down the rate of fall of the body. Drag depends on the contact surface area and weight. More the surface area in contact, more would be the drag. The sitting position of the skydiver would experience less drag than the chest down position because of the less contact surface area of the body with the air molecules while in the former case. No two persons have identical body shape and weight. Hence, the rate of fall can be made nearly equal but not exactly equal. This is would be possible when they are having same body position.

6 0

3 years ago

For a projectile launched from the vertically from the surface the earth with initial velocity v0, the velocity of the projectil

UNO [17]

Answer:

(dr/dt) = √(v₀² + k²/r - k²/R)

Explanation:

v² = v₀² + k²[(1/r) - (1/R)]

v = velocity of Body launched from the surface of the earth

v = initial velocity of body

k = a constant

r = distance from the centre of the earth

R = radius of the earth

v² = v₀² + k²/r - k²/R

v = √(v₀² + k²/r - k²/R)

But v = dr/dt

(dr/dt) = √(v₀² + k²/r - k²/R)

(dr/√(v₀² + k²/r - k²/R)) = dt

To go one step beyond and integrate the differential equation

∫ (dr/√(v₀² + k²/r - k²/R)) = ∫ dt

Integrating the left hand side from 0 to r and the right hand side from 0 to t

Note, v₀, k and R are all constants

(- 4r²/k²)[√(v₀² + k²/r - k²/R)] = t

√(v₀² + k²/r - k²/R) = (- k² t/4r²)

(v₀² + k²/r - k²/R) = (- k² t/4r²)²

(v₀² + k²/r - k²/R) = (k⁴t²/16r⁴)

(k⁴t²/16r⁴) + (k²/r) = [v₀² - (k²/R)]

k² [(k²t²/16r⁴) + (1/r)] = [v₀² - (k²/R)]

[(k²t²/16r⁴) + (1/r)] = [(v₀²/k²) - (1/R)]

3 0

3 years ago

A motorcycle is traveling along a highway at 26 m/s. How far does the motorcycle travel in 15 s?

leva [86]

26 m/s for fifteen seconds. distance = rate times time, so distance = 26 m/s * 15 seconds. this gives you distance = 390 meters.

8 0

3 years ago

The law of conversation of energy states that energy cannot be created or

irinina [24]

Answer:

It says energy can't be created or destroyed

Explanation:

5 0

3 years ago