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2 years ago

4

Um consumidor, ao sair para comprar lâmpadas para a sua casa, se deparou com três tipos, lâmpadas incandescentes, fluorescentes

e de LED. Ele precisa de uma lâmpada que ilumine e produza calor para colocar em seu viveiro de lagartos.
Qual lâmpada ele deve escolher?

2 answers:

maria [59]2 years ago

4 0

I have no idea sorry

vivado [14]2 years ago

4 0

Answer:

CAN U PLS POST THIS IN SPANISH?

Explanation:

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Julius competes in the hammer throw event. The hammer has a mass of 7.26 kg and is 1.215 m long. What is the centripetal force o

nevsk [136]

In the circular motion of the hammer, the centripetal force is given by
$F=m \frac{v^2}{r}$
where m is the mass of the hammer, v its tangential speed and r is the distance from the center of the motion, i.e. the length of the hammer.
Using the data of the problem, we find:
$F=m \frac{v^2}{r}=(7.26 kg) \frac{(31.95 m/s)^2}{1.215 m}=6100 N$

4 0

2 years ago

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Suppose two astronauts on a spacewalk are floating motionless in space, 3.0 m apart. Astronaut B tosses a 15.0 kg IMAX camera to

marta [7]

Answer:

$\frac{ 112.5}{15+m_{A}}=v_{f}$

(we need the mass of the astronaut A)

Explanation:

We can solve this by using the conservation law of the linear momentum P. First we need to represent every mass as a particle. Also we can simplify this system of particles by considering only the astronaut A with an initial speed $v_{iA}$ of 0 m/s and a mass $m_{A}$ and the IMAX camera with an initial speed $v_{ic}$ of 7.5 m/s and a mass $m_{c}$ of 15.0 kg.

The law of conservation says that the linear momentum P (the sum of the products between all masses and its speeds) is constant in time. The equation for this is:

$P_{i}=p_{ic}+p_{iA}\\P_{i}=m_{c}v_{ic}+m_{A} v_{iA}\\P_{i}=15*7.5 + m_{A}*0\\P_{i}=112.5 \frac{kg.m}{s}$

By the law of conservation we know that $P_{i} =P_{f}$

For $P_{f}$ (final linear momentum) we need to treat the collision as a plastic one (the two particles stick together after the encounter).

So:

$P_{i} =P_{f}=112.5\\$

$112.5=(m_{c}+m_{A})v_{f}\\\frac{ 112.5}{m_{c}+m_{A}}=v_{f}\\\frac{ 112.5}{15+m_{A}}=v_{f}$

3 0

2 years ago

The NASA spacecraft Deep Space I was shut down on December 18, 2001, following a three-year journey to the asteroid Braille and

Basile [38]

Answer:

The mass will be "8.86 lb".

Explanation:

The given values are:

Force

= 70,000 mi/h

Speed

= 7900 mi/h

On applying the Law of momentum, we get

⇒ $V_{1}m_{1}=V_{2}m_{2}$

On putting the estimated values, we get

⇒ $70000 = 7900\times mass \ of \ deepspace \ 1$

⇒ $mass \ of \ deepspace \ 1 = \frac{70000}{7900}$

⇒ $=8.86 \ lb$

7 0

2 years ago

A boy throws a 15 kg ball at 4.7 m/s to a 65 kg girl who is stationary and standing on a skateboard. After catching the ball, th

jek_recluse [69]

Answer:

$a)v_{f}=0.88m/s$

Explanation:

To solve this problem we use the Momentum's conservation Law, before and after the girl catch the ball:

$\\ p_{1}=p_{2}\\m_{ball}*v_{o.ball}+m_{girl}*v_{o.girl} = m_{ball}*v_{f.ball} + m_{girl}*v_{f.girl}$ (1)

At the beginning the girl is stationary:

$v_{o.girl}=0m/s$ (2)

If the girl catch the ball, both have the same speed:

$v_{f.girl}=v_{f.ball}=v_{f}$ (3)

We replace (2) and (3) in (1):

$m_{ball}*v_{o.ball} = (m_{ball}+m_{girl})*v_{f} \\$

We can now solve the equation for v_{f}:

$v_{f}=\frac{m_{ball}*v_{o.ball}}{(m_{ball}+m_{girl})}=\frac{15*4.7}{15+65}=0.88m/s$

4 0

2 years ago

yami pours powdered cocoa mix into milk and stirs it. then she microwaves the mixture for three minutes. when she takes the cup

MrRa [10]

Convection can best be observed as she blows the warm steam air that rises.

As the warm steam rises, she forces displaces it with cool air from her mouth. Because the warm steam is less dense it rises and because the cool air is more dense, it displaces the warm air.

This scenario is an example of convection.

6 0

2 years ago

Read 2 more answers