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Naddik [55]
3 years ago
11

Which activity is an example of a chemical change?

Physics
2 answers:
saul85 [17]3 years ago
5 0

C lighting a match is a chemical reaction


melomori [17]3 years ago
3 0

The answer is C because when the chemicals on the tip of a match are heated up from friction it ignites.

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Lexy throws a dart with an initial velocity of 25 m/s at an angle of 60° relative to the ground. what is the approximate vertica
Serjik [45]
An initial velocity is:
v o = 25 m/s
The vertical component of the initial velocity:
v o y = v o * sin 60° =
= v o * √3 / 2 = 25 m/s * √3 / 2 = 21.65 m/s
Answer:
The approximate vertical component of the initial velocity is 21.65 m/s.
7 0
3 years ago
Read 2 more answers
Asteroids do not travel in a straight line as they orbit the Sun. Per Newton's second law of motion, this implies
Morgarella [4.7K]
A force is acting on the planet
7 0
2 years ago
How much work is done when a 214 newton force pushes a sleeping cow 37m across a field.
nata0808 [166]
Hello!

Answer: 
7918 J

Explanation:

We are assuming that the floor (field) is completely horizontal since there's no information about that in the statement. 

We are going to use the following formula:

W= F . Cos \alpha . D

Where:

F=214 N
\alpha =0º
D= 37m

Then, by substituting we have:

W=214N . Cos (0).37m= 7918 N.m=7918 J

8 0
3 years ago
A helicopter flies with an air speed of 175 km/h, heading south. The wind is blowing at 85 km/h to the east relative to the grou
spayn [35]

Answer:

154° at 195 km/h

Explanation:

The helicopter is moving south at 175 km/h, relative to the wind.

But the wind is moving east at 85 km/h, relative to the ground.

This means that the helicopter is moving south east relative to the ground.

Every hour, the helicopter will move 175 km to the south and 85 km to the east, relative to the ground.

This means that we can determine the speed and direction of the helicopter using a right triangle and simple trigonometry.

Refer to the triangle b1.

The distance traveled by the helicopter in 1 hour is denoted by d.

d is the hypotenuse of the right triangle.

Using the Pythagorean Theorem, we can calculate d to be 195 km (rounded to 3 s. f.)

Hence the helicopter is traveling at 195 km/h relative to the ground.

To calculate the direction we use,

tan (x) = opposite/adjacent = 85/175

So the angle x is,

x = arctan (\frac{85}{175} ) = 25.9°

Relative to the North, the helicopter is moving at 180° - 25.9° = 154° (rounded to 3 s. f.)

8 0
2 years ago
Two mirrors are touching so they have an angle of 35.4 degrees with one another. A light ray is incident on the first at an angl
alexandr1967 [171]

Answer:

54.6°

Explanation:

From law of reflection i=r.

So, construct the reflected ray at 55.7°degrees from the normal and let it fall on the other mirror.  

Now draw the second normal at the point of incidence and again measure the angle of incidence, and draw the angle of reflection.

If you consider triangle AOB, one angle is ∠AOB=90°

 and ∠OAB is 54.6°

 

From angle sum property third angle ie ∠ABO=180°-90°-54.6°=35.4°

 

So, the second incident angle will be 54.6°

Hence, the second reflected angle will be 54.6 degrees.

8 0
3 years ago
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