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4 years ago

Choose an example of a vertical motion with a negative velocity and a negative acceleration.

Physics

1 answer:

serious [3.7K]4 years ago

4 0

Answer:

A body falling down towards earth, when upward direction is considered as positive direction got negative velocity and acceleration.

Explanation:

You are standing on top of a building with certain height, H and you select height of building to be positive. If you throw a stone upward it's displacement is increasing and velocity is decreasing, both of them are positive and it is attracted towards earth by an acceleration so it is downward. SO it's value is negative.

After reaching the maximum height the stone comes down and it's velocity increases in the downward direction, in this situation it is having negative velocity and and negative acceleration.

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B. Find the centripetal force needed to keep an 60.0 kg rider traveling in a circle in the ride.

schepotkina [342]

Answer:

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Explanation:

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8 0

3 years ago

Atomic nuclei of almost all elements consist of

wolverine [178]

<h2>Answer: protons and neutrons. </h2>

The atomic nuclei of almost all elements consist of protons and neutrons.

The nucleus of an atom has very small dimensions. However, it occupies its central part and concentrates more than 99% of its total mass.

It is in the nucleus that the protons (positive charge) and neutrons (neutral charge) are found.

4 0

4 years ago

Two stones are launched from the top of a tall building. One stoneis thrown in a direction 30.0^\circ above the horizontal with

Butoxors [25]

Answer:

Part A)

t(1) > t(2), the stone thrown 30 above the horizontal spends more time in the air.

Part B)

x(f1) > x(f2), the first stone will land farther away from the building.

Explanation:

Part A)

Let's use the parabolic motion equation to solve it. Let's define the variables:

y(i) is the initial height, it is a constant.
y(f) is the final height, in our case is 0
v(i) is the initial velocity (v(i)=16 m/s)
θ1 is the first angle, 30°
θ2 is the first angle, -30°

For the first stone

$y_{f1}=y_{i1}+v*sin(\theta_{1})t_{1}-0.5gt_{1}^{2}$

$0=y_{i1}+16*sin(30)t_{1}-0.5*9.81*t_{1}^{2}$

$0=y_{i1}+8t_{1}-4.905*t_{1}^{2}$ (1)

For the second stone

$0=y_{i2}+16*sin(-30)t_{2}-4.905t_{2}^{2}$

$0=y_{i2}-8t_{2}-4.905t_{2}^{2}$ (2)

If we solve the equation (1) we will have:

$t_{1}=\frac{-8\pm \sqrt{64+19.62*y_{i}}}{-9.81}$

We can do the same procedure for the equation (2)

$t_{1}=\frac{8\pm \sqrt{64+19.62*y_{i}}}{-9.81}$

We can analyze each solution to see which one spends more time in the air.

It is easy to see that the value inside the square root of each equation is always greater than 8, assuming that the height of the building is > 0. Now, to get positive values of t(1) and t(2) we need to take the negative option of the square root.

Therefore, t(1) > t(2), it means that the stone thrown 30 above the horizontal spends more time in the air.

Part B)

We can use the equation of the horizontal position here.

First stone

$x_{f1}=x_{i1}+vcos(30)t_{1}$

$x_{f1}=0+13.86*t_{1}$

$x_{f1}=13.86*t_{1}$

Second stone

$x_{2}=x_{i2}+vcos(-30)t_{2}$

$x_{1}=0+13.86*t_{1}$

$x_{1}=13.86*t_{2}$

Knowing that t(1) > t(2) then x(f1) > x(f2)

Therefore, the first stone will land farther away from the building.

They land at different points at different times.

I hope it helps you!

3 0

3 years ago

Explain what happens to the particles in a substance during a physical change.

omeli [17]

Answer:

In physical changes no new materials are formed and the particles do not change apart from gaining or losing energy. ... Particles stay the same unless there is a chemical change whether the matter is solid, liquid or gas. Only their arrangement, energy and movement changes.

Explanation:

Hope this helps

7 0

3 years ago

Read 2 more answers

In making the determination that bullets, shells, or cartridge cases were fired from a specific weapon, the criminalist would us

ss7ja [257]

Answer:

Comparison Microscope

Explanation:

The Comparison Microscope allows for comparison between two objects or samples by placing them side by side.

It is primarily used in criminology for ballistics which makes it ideal to find out if bullets, shells, or cartridge cases were fired from a specific weapon.

7 0

3 years ago