All categories

3 years ago

If an atom has 34 protons and 40 neutrons, what is its mass number?

Physics

2 answers:

Liula [17]3 years ago

7 0

The answer is 74

The mass equals the number protons and neutrons.

34+40= 74

natta225 [31]3 years ago

5 0

Mass number is the total of neutrons and protons added together therefore it is 34+40 which is 74. This is the mass number for the atom.

You might be interested in

A plane starting from rest accelerates to 40 m/s in 10 s. How far did the plane travel during this time?

andrew-mc [135]

Answer:

400 meters

Explanation:

using the equation:

speed = distance/time
it would look like this when plugged in: 40=d/10
d (distance) is the unknown variable, so you have to solve for that
multiply both sides by 10 since you want to separate d to solve its number.
10d/10=40 × 10
the two tens on the d part of the equation would cancel out, leaving only d.
Therefore, d = 400

Hopefully this helps.

5 0

3 years ago

A vehicle hits a bridge abutment at a speed estimated by

Ugo [173]

Answer:

54.5 kmph

Explanation:

From work-kinetic energy principles, work done by friction on both pavement and gravel shoulder = kinetic energy change of vehicle

ΔK = W = -(f₁d₁ + f₂d₂) where f₁ = frictional force due to pavement = μ₁mg where μ₁ = coefficient of friction of pavement = 0.35, m = mass of vehicle and g = acceleration due to gravity = 9.8 m/s² and d₁ = distance moved by vehicle across pavement = 30 m and

f₂ = frictional force due to gravel shoulder = μ₂mg where μ₂ = coefficient of friction of pavement = 0.50, m = mass of vehicle and g = acceleration due to gravity = 9.8 m/s² and d₂ = distance moved by vehicle across gravel shoulder = 60 m

ΔK = 1/2m(v₁² - v₀²) where v₀ = initial velocity of vehicle, v₁ = final velocity of vehicle = 20 kmph = 20 × 1000/3600 = 5.56 m/s and m = mass of vehicle

So,

ΔK = -(f₁d₁ + f₂d₂)

1/2m(v₁² - v₀²) = -(μ₁mgd₁ + μ₂mgd₂)

1/2(v₁² - v₀²) = -(μ₁gd₁ + μ₂gd₂)

v₁² - v₀² = -2g(μ₁d₁ + μ₂d₂)

v₀² = v₁² + 2g(μ₁d₁ + μ₂d₂)

v₀ = √[v₁² + 2g(μ₁d₁ + μ₂d₂)]

substituting the values of the variables into the equation, we have

v₀ = √[(5.56 m/s)² + 2 × 9.8 m/s²(0.35 × 30 m + 0.5 × 60 m]

v₀ = √[30.91 (m/s)² + 4.9 m/s²(10.5 m + 30 m]

v₀ = √[30.91 (m/s)² + 4.9 m/s²(40.5 m]

v₀ = √[30.91 (m/s)² + 198.45 (m/s)²]

v₀ = √[229.36 (m/s)²

v₀ = 15.14 m/s

v₀ = 15.14 × 3600/1000

v₀ = 54.5 kmph

So, the initial speed of the vehicle is 54.5 kmph

5 0

3 years ago

When you push a child on a swing, your action is most effective when your pushes are timed to coincide with the natural frequenc

OleMash [197]

Answer:

$T = 4.48 s$

we can see that this time period is independent of the mass of the child so answer would be same if the child mass is different

Explanation:

Natural frequency of a simple pendulum of L length is given as

$f = \frac{1}{2\pi}\sqrt{\frac{g}{L}}$

so the time period of the oscillation is given as

$T = 2\pi \sqrt{\frac{L}{g}}$

so we will have

$L = 5 m$

$T = 2\pi\sqrt{\frac{5}{9.81}}$

$T = 4.48 s$

also from above formula we can see that this time period is independent of the mass of the child so answer would be same if the child mass is different

3 0

4 years ago

Rock formed from the crystallization of magma is called

xz_007 [3.2K]

A rock formed from the crystallization of magma is called an igneous rock. We know this rock forms from the cooling and / or solidification of lava or magma - usually from volcanoes, most of the time.

3 0

3 years ago

Consider the specific example of a positive charge q moving in the +x direction with the local magnetic field in the +y directio

Leto [7]

Answer:

Therefore the direction is in the <u>positive direction of the z axes</u>.

Explanation:

Let's recall that the magnetic force is given by:

$F_{B}=q(\vec{v} \times \vec{B})$