Please help me i give 60 point i need help now

Which of these is an example of a physical change? Question options: wood decaying iron melting paper burning steel rusting

marin [14]

Im pretty sure burning paper

its either that or melting iron but im 90 percent sure its paper burning

4 0

3 years ago

A 5.10 kgkg watermelon is dropped from rest from the roof of a 18.5 mm-tall building and feels no appreciable air resistance.

VARVARA [1.3K]

Work done is by the change in the potential energy of the system. The work done by gravity is 924.63 J.

<h3>What is the Kinetic Energy?</h3>

Potential energy in physics is the energy that an item retains as a result of its position in relation to other objects, internal tensions, electric charge, or other elements.
The gravitational potential energy of an object, which is based on its mass and distance from another object's center of mass, the elastic potential energy of an extended spring, and the electric potential energy of an electric charge in an electric field are examples of common types of potential energy. The joule, denoted by the letter J, is the energy unit in the International System of Units (SI).

Solution:

mass = 5.10 kg

height = 18.5 mm

We know that work done by the gravity on the watermelon is the change in the potential energy of the watermelon, therefore,

Work done due to gravity = change in the potential energy of the system

W = $\Delta PE$

W = mg (h₀ - h₁)

W = 5.10 × 9.8 × 18.5

W = 924.63 J

know more about potential energy brainly.com/question/24284560

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7 0

1 year ago

A child slides down a hill on a toboggan with an acceleration of 1.8 m/s^2. If she starts at rest, how far has she traveled in :

DENIUS [597]

Explanation:

It is given that,

The acceleration of the toboggan, $a=1.8\ m/s^2$

Initial speed of the toboggan, u = 0

We need to find the distance covered by the toboggan. Using the second equation of motion as :

$s=ut+\dfrac{1}{2}at^2$

At t = 1 s

$s=\dfrac{1}{2}\times 1.8\times 1^2$

$s_1=0.9\ m$

At t = 2 s

$s=\dfrac{1}{2}\times 1.8\times 2^2$

$s_2=3.6\ m$

At t = 3 s

$s=\dfrac{1}{2}\times 1.8\times 3^2$

$s_3=8.1\ m$

Hence, this is the required solution.

4 0

3 years ago

The Franck-Hertz experiment involved shooting electrons into a low-density gas of mercury atoms and observing discrete amounts o

Anuta_ua [19.1K]

Answer:

the final kinetic energy is 0.9eV

Explanation:

To find the kinetic energy of the electron just after the collision with hydrogen atoms you take into account that the energy of the electron in the hydrogen atoms are given by the expression:

$E_n=\frac{-13.6eV}{n^2}$

you can assume that the shot electron excites the electron of the hydrogen atom to the first excited state, that is

$E_{n_2-n_1}=-13.6eV[\frac{1}{n_2^2}-\frac{1}{n_1^2}]\\\\E_{2-1}=-13.6eV[\frac{1}{2^2}-\frac{1}{1}]=-10.2eV$

-10.2eV is the energy that the shot electron losses in the excitation of the electron of the hydrogen atom. Hence, the final kinetic energy of the shot electron after it has given -10.2eV of its energy is:

$E_{k}=11.1eV-10.2eV=0.9eV$

6 0

3 years ago

Rank the six combinations of electric charges on the basis of the electric force acting on q1. Define forces pointing to the rig

riadik2000 [5.3K]

Answer:

Plss see attached file

Explanation:

3 0

3 years ago