Can an object have increasing speed while its acceleration is decreasing?

Which of the following is not an example of a chemical reaction? Rust, Photosynthesis, Melting Ice, Heat from Fire?

FinnZ [79.3K]

Rust, photosynthesis, and heat from fire are all chemical reactions <span>because </span>new substances are formed and the chemical formula is changed. By doing this, bonds are broken and formed in the making of the new substance. Melting ice is physical change the molecules are still water molecules, it just changed physical form.

5 0

2 years ago

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aluminum has 13 electrons. how many electrons are found in the outermost energy level for this atom which energy level is the ou

Stolb23 [73]

<span>The outermost energy level of an element are called the valence shell, that holds the valence electrons. they consist of the highest energy level. In aluminum, the valence electrons are 3. </span>

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2 years ago

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Leah is moving in a spaceship at a constant velocity away from a group of stars. Which one of the following statements indicates

OLEGan [10]

Answer:

E) She can perform no measurement to determine this quantity.

Explanation:

A spacecraft is a machine used to fly in outer space.

According to Isaac Newton's third law of motion, every action produces an equal and opposite reaction. When fuel is shoot out of one end of the rocket, the rocket moves forward for which no air is required.

As Leah is moving in a spaceship at a constant velocity away from a group of stars, she cannot measure to determine this quantity.

5 0

2 years ago

A playground merry-go-round has radius 2.40 m and moment of inertia 2100 kg⋅m2 about a vertical axle through its center, and it

daser333 [38]

Answer:

a) 0.31 rad/s

b) 100 J

c) 6.67 W

Explanation:

(a) the force would generate a torque of:

$T = FR = 18 * 2.4 = 43.2 Nm$

According to Newton 2nd law, the angular acceleration would be

$\alpha = \frac{T}{I} = \frac{43.2}{2100} = 0.021 rad/s^2$

It starts from rest, then after 15s it would achieve a speed of

$\omega = \alpha t = 0.021 * 15 = 0.31 rad/s$

(b) The distance angle swept by it is:

$\theta = \frac{\alpha t^2}{2} = \frac{0.021 * 15^2}{2} = 2.314 rad$

Hence the work by the child

$W = T\theta = 43.2 *2.314 \approx 100 J$

c) Average power to work per time unit

$P = \frac{W}{t} = \frac{100}{15} = 6.67 W$

7 0

2 years ago

A toy car starts from the rest and accelerates at 1.50m/s2 [E] for 2.25s. What is the final velocity, of the car

V125BC [204]

3.375m/s is the final velocity of the car.

<h3>How do you find final velocity?</h3>

The final velocity depends on how large the acceleration is and the distance over which it acts.

Initial velocity of an object, you can multiply the acceleration due to a force by the time the force is applied and add it to the initial velocity to get the final velocity.

According to the question,

A toy car starts from the rest and accelerates

So the acceleration = 1.50m/s²

Time = 2.25s

$x=x_{0} + vt$