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Firlakuza [10]
3 years ago
5

Which is a sign of a chemical change? A) Ice cream left at room temperature melts. B) Calcium chloride is dissolved in H2O and d

isappears. C) Paint on a freshly painted wall dries and is no longer sticky. D) When H2S gas is bubbled into a lead acetate solution, a precipitate forms.
Physics
2 answers:
Eduardwww [97]3 years ago
7 0

D, because a physical change is when something changes but doesn't change into a new substance. A chemical change is when something changes into a new substance.

Katarina [22]3 years ago
5 0
Chemical change is any change that results in the formation of new chemical substances. (Thanks to google)

This the answer is D
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Which observation is the best evidence that some colors of visible light are
Effectus [21]

Answer:

id say D

Explanation:

because its the only answer that has to do with colors and visable light

but A and B also have to do with eachother so i feel like it could be with one of those but it def isnt C

I am sorry if i am wrong, let me know tho!

8 0
3 years ago
Read 2 more answers
Which circuit offers the greater resistance to the battery, two bulbs in series or two bulbs in parallel?
dolphi86 [110]

The resistance of two things in series is the SUM of their individual resistances.  So the resistance of two bulbs in series is <u><em>double</em></u> the resistance of one bulb.

(If they're in parallel, their combined resistance is <u><em>1/2</em></u> the resistance of one bulb.)

So two bulbs <em>in series</em> is the greater resistance. <em>(a) </em>

7 0
3 years ago
a diver on a board 7.5m above the water walks off the end with a horizontal velocity of 2.3 m/s when they hit the surface of the
m_a_m_a [10]

Answer:

2.846m

Explanation:

The diver is performing projectile motion.

To find x(final), we are going to use the equation x(final) = v(initial)*t + x(initial)

x(initial) = 0

x(final) = ?

v(initial) = 2.3 m/s

we don't know t

To find t we will use y(final) = 1/2*(-9.8)*t^2 + v(initial in the y dir.)*t + y(initial)

- 9.8 in the acceleration in the y dir.

y(final) = 0

y(initial) = 7.5

v(initial in the y dir.) = 0

If we solve for t we get: t = 1.237s

Now we have all the components to solve for x(final) in x(final) = v(initial)*t + x(initial)

x(final) = 2.3*1.237 + 0

x(final) = 2.846m

6 0
3 years ago
If R = 12 cm, M = 520 g, and m = 20 g (below), find the speed of the block after it has descended 50 cm starting from rest. Solv
timofeeve [1]

Answer:

v = 0.84 m/s

Explanation:

given,

R = 12 cm

M (mass of pulley )= 520 g

m  (mass of block)=  20 g

s = 50 cm = 0.5 m

using conservation of energy

Potential energy = Kinetic energy

 m g h = \dfrac{1}{2}mv^2 + \dfrac{1}{2}I\omega^2

   I_{disk}= \dfrac{1}{2}MR^2  and v = r ω

 m g h = \dfrac{1}{2}mv^2 + \dfrac{1}{2}(\dfrac{1}{2}MR^2)(\dfrac{v}{R})^2

 m g h = \dfrac{1}{2}mv^2 +\dfrac{1}{4}Mv^2

 m g h = \dfrac{1}{2}v^2(m +\dfrac{1}{2}M)

 v=\sqrt{\dfrac{2mgh}{m + 0.5 M}}

 v=\sqrt{\dfrac{2\times 0.020 \times 9.8 \times 0.5}{0.02 + 0.5\times 0.52}}

      v = √0.7

      v = 0.84 m/s

5 0
3 years ago
A marble rolls off a tabletop 1.15 m high and hits the floor at a point 4 m away from the tables edge in the
GREYUIT [131]

A marble rolls off a tabletop 1.15 m high and hits the floor at a point 4 m away from the edge of the table in the horizontal direction,

  • t= 0.45 seconds.
  • V=2.22m/s
  • VT=4.95 m/s

This is further explained below.

<h3>What is its speed when it hits the floor...?</h3>

Generally, the equation for motion is mathematically given as

S= ut + 0.5at²

Therefore

y = Voy t + 0.5gt^2

1 = 0.5x 98 x 6²

1=4.9t^2

t=\sqrt{0.2041 }

t= 0.45 seconds.

b) Horizontal motions are uniform.

V=Horizontal displacement/time

V=1/0.45

V=2.22m/s

C)

Vx: 2.22 m/s At bottom,

Vy² = Voy² + 2as

Vy² = 2x95x1

Vy² = 19.6

Total velocity

VT=\sqrt{( 2.22 m/)^2+19.6}

VT=4.95 m/s

Read more about  Arithmetic

brainly.com/question/22568180

#SPJ1

4 0
2 years ago
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