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2 years ago

Who was th efirst person to come up with the idea of the atoms.

Physics

1 answer:

Gwar [14]2 years ago

7 0

Answer:

Democritus

Explanation:

Democritus was a Greek philosopher who was the first person to use the term atom . However ,John Dalton was the first to adapt Democritus’ theory into the first modern atomic

model

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Can you find the magnetic field based on force? a straight segment of wire 35.0 cm long carrying a current of 1.40 a is in a uni

Lostsunrise [7]

The force exerted by a magnetic field on a wire carrying current is:
$F=ILB \sin \theta$
where I is the current, L the length of the wire, B the magnetic field intensity, and $\theta$ the angle between the wire and the direction of B.

In our problem, the force is F=0.20 N. The current is I=1.40 A, while the length of the wire is L=35.0 cm=0.35 m. The angle between the wire and the magnetic field is $53 ^{\circ}$ , so we can re-arrange the formula and substitute the numbers to find B:
$B= \frac{F}{IL \sin \theta}= \frac{0.20 N}{(1.40 A)(0.35 m)(\sin 53^{\circ})}=0.51 T$

3 0

2 years ago

At t=0, a train approaching a station begins decelerating from a speed of 80 mi/hr according to the acceleration function a(t)=−

vredina [299]

Answer:

a) Δx = 49.23 mi , b) Δx = 5.77 mi

Explanation:

As we have an acceleration function we must use the definition of kinematics

a = dv / dt

∫dv = ∫ a dt

we integrate and evaluators

v - vo = ∫ (-1280 (1 + 8t)⁻³ dt = -1280 ∫ (1+ 8t)⁻³ dt

We change variables

1+ 8t = u

8 dt = du

v - v₀ = -1280 ∫ u⁻³ du / 8

v -v₀ = -1280 / 8 (-u⁻²/2)

v - v₀ = 80 (1+ 8t)⁻²

We evaluate between the initial t = 0 v₀ = 80 and the final instant t and v

v- 80 = 80 [(1 + 8t)⁻² - 1]

v = 80 (1+ 8t)⁻²

We repeat the process for defining speed is

v = dx / dt

dx = vdt

x-x₀ = 80 ∫ (1-8t)⁻² dt

x-x₀ = 80 ∫ u⁻² dt / 8

x-x₀ = 80 (-1 / u)

x-x₀ = -80 (1 / (1 + 8t))

We evaluate for t = 0 and x₀ and the upper point t and x

x -x₀ = -80 [1 / (1 + 8t) - 1]

We already have the function of time displacement

a) let's calculate the position at the two points and be

t = 0 h

x = x₀

t = 0.2 h

x-x₀ = -80 [1 / (1 +8 02) -1]

x-x₀ = 49.23

displacement is

Δx = x (0.2) - x (0)

Δx = 49.23 mi

b) in the interval t = 0.2 h at t = 0.4 h

t = 0.4h

x- x₀ = -80 [1 / (1+ 8 0.4) -1]

x-x₀ = 55 mi

Δx = x (0.4) - x (0.2)

Δx = 55 - 49.23

Δx = 5.77 mi

3 0

3 years ago

A ball is projected upward at time t = 0.0 s, from a point on a roof 70 m above the ground. The ball rises, then falls and strik

pentagon [3]

Answer:

The velocity of a ball will be "-70.13 m/s".

Explanation:

The given values are:

u = 70 m

t = 0.0 s

g = a = -9.8 m/s²

s = -1 m

v = ?

As we know,

The equation of motion will be:

⇒ $v^2-u^2=2as$

On substituting the estimated values, we get

⇒ $v^2-(70)^2=2\times (-9.8)\times (-1)$

⇒ $v^2-4900=19.6$

⇒ $v^2=19.6+4900$

⇒ $v^2=4919.6$

⇒ $v=\sqrt{4919.6}$

⇒ $v=70.13 \ m/s$

In downward direction, it will be:

⇒ $v=-70.13 \ m/s$

8 0

2 years ago

What are comets made of?

qaws [65]

<h2>Comets are made of Chunks of rock, gas, Ice, and dust. The Answer is A and C.</h2>

Explanation:

Comets is one of the main types of space rocks. Recent researchers has termed Comets as 'dirty snowballs' of space, that contains ice, rock, gas and dust. The solid center of the comet is less than 10 kilometers across.

Comets are believed to have originated beyond Neptune and Pluto. It is called the Oort Cloud that surrounds the solar system.

It carries carbon dioxide, methane, ammonia, and many more gases. According to Astronomers, comets are assumed to be the leftovers of the material that was initially the part of solar system about billion years ago.

3 0

3 years ago

Read 2 more answers

A person skateboarding is part of a closed system that has 1,450 j of

soldier1979 [14.2K]

The gravitational potential energy of the system will decreases from 1,250 J to 625 J. Option A is corect.

<h3>What is the law of conservation of energy?</h3>

According to the Law of Conservation of Energy, energy can neither be created nor destroyed, but it can be transferred from one form to another.

The total energy is the sum of all the energies present in the system. The potential energy in a system is due to its position in the system.

TE=KE+GPE

Case 1;

1450 = 200 J+GPE

GPE=1450 -200

GPE=1250 J

Case 2;

1450 = 825 J+GPE

GPE=1450 -825

GPE=625 J

The gravitational potential energy of the system will decreases from 1,250 J to 625 J.

Hence, option A is corect.

To learn more about the law of conservation of energy, refer to brainly.com/question/2137260.

#SPJ1

6 0

2 years ago