2 Here are some numbers: 22 23 25 27 29 ܕ ST From the list, write down all of the prime numbers .

Looking at the examples below and select the change in matter that is an example of a physical change A Ice Melting B leaves cha

Gnesinka [82]

Answer:

- As an ice cube melts, its shape changes as it acquires the ability to flow. ... A physical change is a change to a sample of matter in which some ... The salt may be regained by boiling off the water, leaving the salt ... The resulting mixture is a solution with a pale green color. ... Answer b: chemical change.

Explanation:

8 0

3 years ago

A 2000 Hz siren and a civil defense official are both at rest with respect to the ground. What frequency does the official hear

astra-53 [7]

Answer:

a) $f_1 = 2070.6 Hz$

b) $f_2 = 1929.4 Hz$

Explanation:

Apparent frequency of the siren is given as

$f = \frac{v_{rel}}{\lambda}$

as we know that the wavelength will remain the same as it is having originally

sowe know

$\lambda = \frac{340}{2000}$

$\lambda = 0.17 m$

a) Now when wind is blowing from source to official

so we have

$v_{rel} = 340 + 12 = 352 m/s$

so we have

$f_1 = \frac{352}{0.17}$

$f_1 = 2070.6 Hz$

b) Now when wind is from official to source

so we have

$v_{rel} = 340 - 12 = 328 m/s$

so we have

$f_2 = \frac{328}{0.17}$

$f_2 = 1929.4 Hz$

4 0

4 years ago

A ball at the top of a hill is an example of ______ and a ball rolling down the hill is an example of ______.

larisa [96]

Potential energy , Kinetic energy

<h3 /><h3>What is kinetic energy and potential energy?</h3>

Kinetic energy is a form of energy that posses by an object due to its motion. If work, which transfers energy, is done on an object by applying a net force, the object speeds up and thereby gains kinetic energy.

Potential energy is the energy held by an object due to its position relative to other objects, stresses within itself, its electric charge, or other factors.

According to given condition,

At first,

When a ball is at the top of a hill , it posses a potential energy because the ball is at some height from the surface where the energy held by ball is due to its position.

That is why, a ball at the top of a hill is an example of Potential energy.

Secondly,

When a ball is rolling down the hill , it posses kinetic energy because the ball have some energy that posses by an object due to its motion.

That is why, a ball rolling down the hill is an example of Kinetic energy.

Learn more about Potential energy and Kinetic energy here:

brainly.com/question/11749818

#SPJ1

6 0

2 years ago

A girl and a boy pull in opposite directions on strings attached to each end of a spring balance. Each child exerts a force of 2

BabaBlast [244]

Answer:

yo they deleted my answer. The answer is 0N

Explanation:

so when two forces pull on an object from opposite sides with the same force (in this case its 20N), then the object is in equilibrium at 0N.

So its clear that there is one person on the the opposite side.

SOOO generally<u>: (left or down) would be considered </u><u>negative</u><u> in an equation. And the other person (right or up) would be considered </u><u>positive</u><u>.</u> So if both forces are the same numbers on opposite sides then the answer is 0 (if you add both of them).

<em>0 is the number of equilibrium.</em>

OK, so the equation would be -20N + 20N and then badda bing badda boom viola, the answer: 0N

thanks for coming to my TED talk. I hope they don't delete this answer.

5 0

3 years ago

The muzzle velocity of a bullet fired from a new rifle is 100 m/s. Neglecting air resistance, at the end of one second a bullet

Burka [1]

Answer:

C. (100+4.9)m

Explanation:

u = 100m/s, t = 1 sec, g = 9.8m/s^2

s = ut + 1/2gt^2

s = 100×1 + 1/2×9.8×1^2 = 100+4.9

s = (100+4.9)m

8 0

3 years ago