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Ludmilka [50]
3 years ago
11

Mary has a mass of 40 kg and sprints at 1 m/s. How much kinetic energy does she have?

Physics
1 answer:
Sav [38]3 years ago
8 0

Answer:

20 J

Explanation:

Kinetic energy is given as half of the product of mass and the square of velocity of an object:

KE = \frac{1}{2}mv^2

where m = mass = 40 kg

v = velocity = 1 m/s

Hence, Mary's kinetic energy is:

KE = \frac{1}{2} * 40 * 1^2

KE = 20 * 1 = 20 J

She has a kinetic energy of 20 J.

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A circular test track for cars has a circumference of 3.5 kmkm . A car travels around the track from the southernmost point to t
elixir [45]

Answer:

(A) Distance will be equal to 1.75 km

(B) Displacement will be equal to 1.114 km

Explanation:

We have given circumference of the circular track = 3.5 km

Circumference is given by 2\pi r=3.5

r = 0.557 km

(a) It is given that car travels from southernmost point to the northernmost point.

For this car have to travel the distance equal to semi perimeter of the circular track

So distance will be equal to =\frac{3.5}{2}=1.75km

(b) If car go along the diameter of the circular track then it will also go from southernmost point to the northernmost point. and it will be equal to diameter of the track

So displacement will be equal to d = 2×0.557 = 1.114 m

8 0
3 years ago
A piece of wood has a volume of 4.6 cm to the power of 3, and a mass of 3.7 g what is the density of the wood
AysviL [449]

Density is given by:

D = M/V

D = density, M = mass, V = volume

Given values:

M = 3.7g, V = 4.6cm³

Plug in and solve for D:

D = 3.7/4.6

D = 0.80g/cm³

3 0
3 years ago
Given that an electric field of 3×106V/m3×106V/m is required to produce an electrical spark within a volume of air, estimate the
Andre45 [30]

Answer:

Length, l = 33.4 m

Explanation:

Given that,

Electrical field, E=3\times 10^6\ V/m

Let the electrical potential is, V=10^8\ V

We need to find the length of a thundercloud lightning bolt. The relation between electric field and the electric potential is given by :

V=E\times d\\\\d=\dfrac{V}{E}\\\\d=\dfrac{10^8}{3\times 10^6}\\\\d=33.4\ m

So, the length of a thundercloud lightning bolt is 33.4 meters. Hence, this is the required solution.

5 0
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How does the search for exoplanets help us describe how science requires creativity?
Aliun [14]

Answer:

As the planets are very small and dark in comparison with stars, it makes them very hard to be found from earth.

Explanation:

Astronomy, of course, has a solution for this. As astronomers can't observe planets directly, they decided to observe the stars and search for the effects that planets have on them.

There are many ways of observing the exoplanets: Radial Velocity, Transit Photometry, Microlensing, Astrometry, Direct Imaging, etc.

Before all of this, scientist had to find ways to prove their theories. Most of their time they have spent in giving the creative answers.

Science and creativity are very much connected when we speak about the development of science. Rationality and creativity always go together.

In order to create an idea that other people will consider useful, it is important to use creativity. As no one has the exact answer when it comes to science, the adventure is to research the unknown.

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Answer:

C. Midlife Crisis.

Explanation:

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