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3 years ago

Which of the following is a chemical change?

1 answer:

3 0

a). Water is still H₂O after it freezes.

b). Ice is still H₂O after it melts.

c). Wire is still Cu when it's bent.

d). Paper combines with the O₂ in the air, and turns into
a lot of new compounds when it burns.

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The graph shows the federal budget from 1980 to 2010. In which period did the federal budget show the greatest deficit?

kodGreya [7K]

Answer:

2000 to 2010

Explanation:

sorry I'm just guessing

8 0

2 years ago

A bowler who always left the same three pins standing could be considered a(n) ____ bowler.

RideAnS [48]

A bowler who always left the same 3 pins standing could be considered a C. Precise bowler as from bowling countless number of times he has observed the same amount of pins knocked down each time.

4 0

3 years ago

Tapping the surface of a pan of water generates 17.5 waves per second. If the wavelength of each wave is 45 cm, what is the spee

ElenaW [278]

Answer:

Speed of the wave is 7.87 m/s.

Explanation:

It is given that, tapping the surface of a pan of water generates 17.5 waves per second.

We know that the number of waves per second is called the frequency of a wave.

So, f = 17.5 Hz

Wavelength of each wave, $\lambda=45\ cm=0.45\ m$

Speed of the wave is given by :

$v=f\lambda$

$v=17.5\times 0.45$

v = 7.87 m/s

So, the speed of the wave is 7.87 m/s. Hence, this is the required solution.

5 0

3 years ago

Which one of the following statements concerning the momentum of a system when the net force acting on the system is equal to ze

Alex

Answer:

Explanation:

According to newton's 2nd law rate of change of momentum is directly proportional to the force applied on the body. Since, net Force is zero this means momentum did not change or momentum of the body remained constant.

Hence, the system have constant value of momentum. Therefore, option D is correct.

5 0

3 years ago

if a stone is projected at an angle of 50 degrees to the horizontal with an initial velocity of 50m/s, what is the vertical comp

Vilka [71]

Answer:

38.3 m/s

Explanation:

To find vertical component of initial velocity, you'd have to use sine ratio:

$\displaystyle{\sin \theta = \dfrac{u_y}{u}}$

$\displaystyle{u_y}$ is vertical component of initial velocity and $\displaystyle{u}$ is initial velocity given which is 50 m/s.

A stone is projected at an angle of 50 degrees so $\displaystyle{\theta}$ = 50°. Substitute in the formula:

$\displaystyle{\sin 50^{\circ} = \dfrac{u_y}{50}}\\\\\displaystyle{50 \sin 50^{\circ} = u_y}\\\\\displaystyle{u_y = 38.3 \ \, \sf{m/s}}$

Therefore, the vertical component of initial velocity is approximately 38.3 m/s

(The picture is also attached for visual reference!)

3 0

2 years ago