Why is the melting of ice a physical change?

A 12 g plastic ball is dropped from a height of 2.5 m and is moving at 3.2 m/s just before it hits the floor. How much mechanica

Nataly [62]

Answer:

0.24

Explanation:

Mass of ball= 12g=0.012Kg

height of ball= 2.5m

velocity of ball before falling= 3.2m/s

potential energy of the ball=mgh= 0.012*10*2.5=0.3J

kinetic energy of the ball=0.5*m $v^{2}$ =0.5*0.012*3.2*3.2=0.6J

Loss in mechanical energy during the fall= potential energy- Kinetic energy= 0.3-0.06=0.24J

note: During the fall, the potential energy of the ball is converted to kinetic energy. the loss in energy is due to air resistance.

4 0

3 years ago

What is the centripetal force that holds planets in orbit?

Fudgin [204]

<h2>Answer: Gravity force</h2>

If we approximate the orbit of the planets around the Sun to circular orbits with a uniform circular motion, where the velocity $\vec{V}$ is a vector, whose direction is perpendicular to the radius $r$ of the trajectory; the acceleration $\vec{a}$ is directed towards the center of the circumference (that's why it's called centripetal acceleration).

Now, according to Newton's 2nd law, the force $\vec{F}$ is directly proportional and in the same direction as the acceleration:

$\vec{F}=m.\vec{a}$

Therefore the net force resulting from the movement of a planet orbiting the Sun points towards the center of the circle, this is called Centripetal Force which is a central force that in this case is equal to the gravity force.

8 0

3 years ago

A tuning fork with a frequency of 335 Hz and a tuning fork of unknown frequency produce beats with a frequency of 5.3 when struc

Ganezh [65]

Answer:

Explanation:

Unknown fork frequency is either

335 + 5.3 = 340.3 Hz

or

335 - 5.3 = 329.7 Hz

After we modify the known fork, the unknown fork frequency equation becomes either

(335 - x) + 8 = 340.3

(335 - x) = 332.3

x = 2.7 Hz

or

(335 - x) + 8 = 329.7

(335 - x) = 321.7

x = 13.3 Hz

IF the unknown fork frequency was 340.3 Hz,

THEN the 335 Hz fork was detuned to 335 - 2.7 = 332.3 Hz

IF the unknown fork frequency was 329.7 Hz,

THEN the 335 Hz fork was detuned to 335 - 13.3 = 321.7 Hz

3 0

2 years ago

Light passes through a pair of narrow slits with a 0.67-mm separation. It is found that the fourth bright fringe makes an angle

babunello [35]

Answer:

The wavelength of the light is 555 nm.

Explanation:

according to Bragg's law..

n×λ = d×sin(θ)

n is the fringe number

λ is the wavelength of the light

d is the slit separation

θ is the angle the light makes with the normal at the fringe.

7 0

3 years ago

Many processes help to shape Earth’s surface. Starting with a rock, in what order would you expect the following Earth processes

GuDViN [60]

<span>Like most Earth materials, rocks are created and destroyed in cycles. The rock cycle is a model that describes the formation, breakdown, and reformation of a rock as a result of sedimentary, igneous, and metamorphic processes. </span><span>All rocks are made up of minerals. A mineral is defined as a naturally occurring, crystalline solid of definite chemical composition and a characteristic crystal structure. A rock is any naturally formed, nonliving, firm, and coherent aggregate mass of solid matter that constitutes part of a planet. i don't know if this is right but i hope it helps</span>

3 0

3 years ago