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3 years ago

In what year will there be 8 billion people in the world? 2020 2022 2024 2030

Physics

2 answers:

Morgarella [4.7K]3 years ago

6 0

Answer:

2030

Explanation:

romanna [79]3 years ago

3 0

It is projected to reach eight billion by 24-30. according to current projections the worlds population is likely to reach around nine billion by 35-50

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Un autocar que circula a 81 km/h frena uniformemente con una aceleración de -4,5 m/s2.

horsena [70]

Answer:

a) $\Delta x=56.25 m$

b) imagen adjunta

Explanation:

a) Primero debemos hacer la conversión de 81 km/h a m/s, esto es 22.5 m/s.

Ahora, usando la ecuacion cinemática, en un movimiento acelerado tenemos:

$v_{f}^{2}=v_{0}^{2}+2a \Delta x$

Queremos encontrar la posición hasta detenerse, osea vf = 0.

$\Delta x=\frac{-v_{0}^{2}}{2a}$

$\Delta x=\frac{-22.5^{2}}{-2*4.5}$

$\Delta x=56.25 m$

b) Para este caso el gráfico se encuentra adjunto.

Espero que te sirva de ayuda!

Download pdf

8 0

3 years ago

Newton’s empirical law of cooling/warming of an object is given by ( ), T Tm k dt dT = − where k is a constant of proportionalit

pychu [463]

Answer:

The time for the cake to cool off to room temperature is

approximately 30 minutes.

Let $T_{0}$ = $70^{0}$ F be the temperature and T that of the body

Explanation:

Our Tm = 70, the initial-value problem is

$\frac{DT}{dt}$ = k(T − 70), T(0) = 300

Solving the equation, we get

$\frac{DT}{t-70}$ = kdt

In [T-70]= kt + $C_{1}$

T = 70 + $C_{2}$ $e^{kt}$

Finding he value for $C_{2}$ using the initial value of T (0)= 300, therefore we get:

300=70+ $C_{2}$

$C_{2}$ = 230 therefore

T= 70+ 230 $e^{kt}$

Finding the value for k using T (3) = 200, therefore we get

T (3) = 200

$e^{3k}$ = $\frac{13}{23}$

K = $\frac{1}{3}$ in $\frac{13}{23}$

= -0.19018

Therefore

T(t) = 70+230 $e^{-0.19018}$

4 0

3 years ago

A rock at the top of a 20 meter tall hill.The rock has a mass of 10 kg. How much potentail energy does it have?

ch4aika [34]

P.E.=mgh
= 10x10x20
=2000J

6 0

3 years ago

Give two examples of events that show that the speed of sound is very much slower than the speed of light

jeka94

Answer:

1) Lightning, you see the lightning first and then hear the thunder.

2)When a person far away from you hits a ball with a bat, you can see them striking the ball first and then you will hear the sound of ball striking against the bat.

6 0

3 years ago

Air resistance is an example of what type of friction?

Sav [38]

Well, Air resistance is a special type of friction (you cannot classify it in other categories). That force of air-resistance is often observed to oppose the motion of the object,( like every other frictional forces)

Hope this helps!

4 0

3 years ago