All categories

3 years ago

If a car is moving +14m/s is to stop within 2 seconds, what must the car's acceleration be?

Physics

1 answer:

stellarik [79]3 years ago

4 0

Acceleration is -7 m/s²

Explanation:

initial velocity (u) = 14 m/s

since it's gonna stop,

final velocity (v) = 0m/s

time taken(t) = 2 seconds

now,

a = (v-u)/t

or, a = (0-14)/2

or, a = -14/2

a = -7m/s²

You might be interested in

How much work is required to pull a wagon 6 meters if you use 70 N of force?

yKpoI14uk [10]

Answer:

Explanation:

7 0

4 years ago

Consider the following distribution of objects: a 5.00-kg object with its center of gravity at (0, 0) m, a 3.00-kg object at (0,

Minchanka [31]

Answer:

(-1.5,-1.5)m

Explanation:

we know that:

$X_{cm} = \frac{m_1x_1+m_2x_2....m_nX_n}{m_1+m_2...m_n}$

where $X_{cm}$ is the location of the center of gravity in the axis x, $m_i$ is the mass of the object i and $x_i$ the first coordinate of center of gravity of object i.

so:

$0 = \frac{(5kg)(0)+(3kg)(0)+(4kg)(3)+(8kg)x_4}{5kg+3kg+4kg+8kg}$

Where $x_4$ is the first coordinate of the center of gravity for the fourth object.

Therefore, solving for $x_4$ , we get:

$x_4 = -1.5m$

At the same way:

$Y_{cm} = \frac{m_1y_1+m_2y_2....m_ny_n}{m_1+m_2...m_n}$

where $Y_{cm}$ is the location of the center of gravity in the axis y, $m_i$ is the mass of the object i and $y_i$ the second coordinate of center of gravity of object i. replacing values we get:

$Y_{cm} = \frac{(5kg)(0)+(3kg)(4)+(4kg)(0)+(8kg)y_4}{5+3+4+8}$

Where $y_4$ is the second coordinate of the center of gravity for the fourth object.

solving for $y_4$ :

$y_4 = -1.5m$

It means that the object of mass 8kg have to be placed in the

coordinates (-1.5,-1.5) m.

8 0

3 years ago

How are scientists able to measure the age of earth?

RoseWind [281]

Explanation:

Through the uranium-lead dating, you can establish the age of rocks that formed from 1 million years ago to 4.5 billion years with enough precision. Dating meteorites using this method, It is possible to establish the age of the earth, since these are pieces that are present since the formation of the solar system, so they are approximately the same age as the Earth.

4 0

3 years ago

Calculate the number of cells in a hummingbird assuming the mass of an average cell is ten times the mass of a bacterium

Mazyrski [523]

Answer:

$4\times 10^{12}$

Explanation:

Given that, the mass of an average cell is 10 times the mass of a bacterium.

And we know that the mass of the bacterium is,

$m_{B} =10^{-15}kg$

Now, the mass of an average cell can be calculate by the mass of bacterium,

$m_{c}=10\times m_{B}\\m_{c}=10\times 10^{-15}kg\\m_{c}=10^{-14}kg$

And the average mass of the humming bird is,

$m_{H} =4\times 10^{-2}kg$

And also we know that,

The no cell is defined as the ratio of mass of an object to the mass of the average cell.

Mathematically,

$N=\frac{m_{H}}{m_{c}}$

Therefore,

$N=\frac{4\times 10^{-2}kg}{10^{-14}kg}\\ N=4\times 10^{12}$

Therefore, the number of cell in the humming bird is $4\times 10^{12}$

4 0

3 years ago

According to Newton’s law of universal gravitation, as the mass or one or both bodies increases, what happens to the force of at

wel

Answer:

force increases

Explanation:

Newton's law of universal gravitation states that the force of attraction (gravity) acting between the Earth and all physical objects is directly proportional to the Earth's mass, directly proportional to the physical object's mass and inversely proportional to the square of the distance separating the Earth's center and that physical object.

According to Newton’s law of universal gravitation, as the mass or one or both bodies increases, the force of attraction between the bodies increases.

Mathematically, this is given by the Newton's Second Law of Motion;

Force = mass * acceleration.

3 0

3 years ago