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4 years ago

What is the definition for chemical change

2 answers:

8 0

Chemical change is any change that results in the formation of new chemical substances. At the molecular level, chemical change involves making or breaking of bonds between atoms.

Leni [432]4 years ago

4 0

It is a change that results in a new chemical substance.

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You want to race a hoop, I_{hoop} = MR^2I hoop =MR 2 , a solid sphere, I_{solid sphere} = \frac{2}{5}MR^2I solidsphere = 5 2 MR

Veseljchak [2.6K]

Answer:

The fastest object is the sphere, so it is the winner

Explanation:

To know which object will arrive faster down, let's look for the velocity of the center of mass of each object. Let's use the concept of mechanical energy

Highest point

Em₀ = U = mg y

Lowest point

$Em_{f}$ = K = $K_{rot}$ + $K_{cm}$ = ½ I w² + ½ m $v_{cm}$ ²

Angular velocity is related to linear velocity.

v = w r

w = v / r

$Em_{f}$ = ½ I $v_{cm}$ ²/r² + ½ m $v_{cm}$ ²

$Em_{f}$ = ½ (I / r² + m) $v_{cm}$ ²

Energy is conserved

Em₀ = $Em_{f}$

mg y = ½ (I / r² + m) $v_{cm}$ ²

$v_{cm}$ = √2 g y / (I / mr² +1)

With this expression we can know which object arrives as a higher speed, therefore invests less time and is the winner. Let's calculate the speed of the center of mass of each

Ring

I = m r²

$v_{cm}$ = √ (2 g y / (m r² / mr² + 1))

$v_{cm}$ = √ (2gy 1/2)

$v_{cm}$ = (√ 2gy) 0.707

Solid sphere

I = 2/5 m r²

$v_{cm}$ = √ (2gy / (2/5 m r² / mr² + 1)

$v_{cm}$ = √ (2gy / (7/5))

$v_{cm}$ = √ (2gy 5/7)

$v_{cm}$ = (√ 2gy) 0.845

Cylinder

I = ½ m r²

$v_{cm}$ = √ (2gy / ½ mr² / mr² + 1)

$v_{cm}$ = √ (2gy / (3/2))

$v_{cm}$ = √ (2g y 2/3)

$v_{cm}$ = (√ 2gy) 0.816

The fastest object is the sphere, so it is the winner when descending the ramp

4 0

3 years ago

Earth is the only planet able to support what

saw5 [17]

Life... obviously lol

8 0

4 years ago

Read 2 more answers

"Consider the Earth and the Moon as a two-particle system. (a) How far from the center of the Earth is the gravitational field o

olga55 [171]

a is the correct

Explanation:

hope you like then comment

3 0

3 years ago

Describe what is happening to the speed during the period (I). 0s - 10s __________________________________________________ (II).

aleksley [76]

Answer:

- There was a constant acceleration at 0 to 10s

- There was a zero acceleration at 10 to 25s

- There was a constant deceleration at 25 to 30s

Explanation:

See attachment for complete question.

Solving (a): What happens at 0s to 10s

There was a constant acceleration and this is proven below.

At time 0, velocity = 15

At time 10, velocity = 30

This is represented as:

$(t_1,v_1) = (0,15)$

$(t_2,v_2) = (10,30)$

Acceleration (A) is the rate of change of velocity against time.

So:

$A = \frac{v_2 - v_1}{t_2-t_1}$

$A = \frac{30-15}{10 - 0}$

$A = \frac{15}{10}$

$A = 1.5$

Since the acceleration is positive, then it shows a constant acceleration.

Solving (b): What happens at 10s to 25s

There was a zero acceleration and this is because the velocity do not change.

See proof below

At time 10, velocity = 30

At time 25, velocity = 30

This is represented as:

$(t_1,v_1) = (10,30)$

$(t_2,v_2) = (25,30)$

Acceleration (A) is the rate of change of velocity against time.

So:

$A = \frac{v_2 - v_1}{t_2-t_1}$

$A = \frac{30-30}{25 - 10}$

$A = \frac{0}{15}$

$A = 0$

Solving (c): What happens at 25s to 30s

There was a constant deceleration and this is proven below.

At time 25, velocity = 30

At time 30, velocity = 0

This is represented as:

$(t_1,v_1) = (25,30)$

$(t_2,v_2) = (30,0)$

Acceleration (A) is the rate of change of velocity against time.

So:

$A = \frac{v_2 - v_1}{t_2-t_1}$

$A = \frac{0-30}{30-25}$

$A = \frac{-30}{5}$

$A = -6$

Since the acceleration is negative, then it shows a constant deceleration

4 0

3 years ago

How did the sun moon and the earth make seasons?

lisov135 [29]

Seasons happen because Earth's axis is tilted at an angle of about 23.4 degrees and different parts of Earth receive more solar energy than others.

4 0

3 years ago