PLEASE HELP!!! PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

1 answer:

4 0

For the first one, the correct answer would be "<span>Substance changes its form but not its molecular composition.". During a physical change (let's say cutting paper), the substance has its shape changed, but it is still itself (paper).

</span><span>The second one is a bit trickier: </span>
Kinetic energy of a molecule is directly influenced by temperature. If there is a higher temperature it will have a higher kinetic energy which means the molecule moves at a higher velocity. This will increase the chance of particles bouncing off of each other during the chemical reaction. That explains why the rate of reaction will be higher at a higher temperature, rather than higher at a cool temperature. The correct answer would be lower at 39F.

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A cork floating in a lake is bobbing in simple harmonic motion. Its displacement above the bottom of the lake is modeled by푦=0.2

Diano4ka-milaya [45]

Explanation:

The displacement pf the bob is modeled by the following equation as :

$y=0.2\ cos20\pi t+0.8$ ..............(1)

The general equation of simple harmonic motion is given by :

$y=A\ cos\ \omega t+\phi$ ...........(2)

On comparing equation (1) and (2) we get :

(a) $\omega=20\pi$

$\omega=20\pi$

$2\pi f=20\pi$

f is the frequency of the motion of the cork.

$f=10\ Hz$

(b) In the equation (1), the displacement of the cork is 0.2. So, the maximum displacement of the cork above the lake bottom is 0.2 + 8 = 8.2 meters

Hence, this is the required solution.

4 0

4 years ago

How high would a 20 kg mass have to be raised to have a gravitational potential energy of 1,000 J?

Vsevolod [243]

We can solve using the formula for gravitational potential energy(GPE = mgh)

M(mass) = 20 kg
g(gravitational constant) = 9.8 m/s^2
GPE = 1000

1000 = 20*9.8*h
1000 = 196h
h = 5.102 meters

8 0

3 years ago

Help me please I need to turn it in before midnight...

ale4655 [162]

Answer:

The statement which explains how the total time spent in the air is affected as the projectile's angle of launch increases from 25 degrees to 50 degrees is;

C. Increasing the angle from 25° to 50° will increase the total time spent in the air

Explanation:

The equation that can be used to find the total time, T, spent in the air of a projectile is given as follows;

$T = \dfrac{2 \cdot u \cdot sin(\theta) }{g}$

Where;

T = The time of flight of the projectile = The time spent in the air

u = The initial velocity of the projectile

θ = The angle of launch of the projectile

g = The acceleration due to gravity ≈ 9.81 m/s²

Given that sin(50°) > sin(25°), when the angle of launch, θ, is increased from 25 degrees to 50 degrees, we have;

Let T₁ represent the time spent in the air when the angle of launch is 25°, and let T₂ represent the time spent in the air when the angle of launch is 50°, we have;

$T_1 = \dfrac{2 \cdot u \cdot sin(25^{\circ}) }{g}$