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3 years ago

Can someone help??

Physics

1 answer:

Paul [167]3 years ago

8 0

Answer:

F = 2520 N

Explanation:

We have,

The maximum acceleration of a fist in a karate punch is 4200 m/s². The mass of the fist is 0.6 kg.

It is required to find the force that the wood place on the fist. Force is given by the product of mass and its acceleration such that,

F = ma

$F=0.6\times 4200\\\\F=2520\ N$

So, the force of 2520 N is acting on the wood.

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Why is pure oxygen stored as a liquid under pressure

yKpoI14uk [10]

<h2>Answer: It is highly flammable.</h2>

Explanation:

Liquid oxygen is created from oxygen atoms that have been forced to assume the liquid state due to <u>compression (change of pressure) and temperature modification. </u>

Specifically this is achieved by cooling the oxygen enough to change it to its liquid state. So,<u> as the temperature drops, the atoms move more slowly because they have less energy. </u>

In this sense, in the liquid state it is easier to store and mobilize oxygen, taking into account that it is a highly flammable gas.

3 0

3 years ago

A hotel elevator ascends 200m with maximum speed of 5m/s. Its acceleration and deceleration both have a magnitude of 1.0m/s2. Pa

ValentinkaMS [17]

Answer:

45 s .

Explanation:

The accelerator will first accelerate , then move with uniform velocity and at last it will decelerate to rest .

displacement s = ?

acceleration a = 1 m /s²

Final speed v = 5 m/s

initial speed u = 0

v² = u² + 2as

5² = 0 + 2 x 1 x s

s = 12.5 m

B) Let time of acceleration or deceleration be t

v = u + a t

5 = 0 + 1 t

t = 5 s

Similarly displacement during deceleration = 12.5 m

Total distance during uniform motion = 200 - ( 12.5 + 12.5 ) = 175 m .

velocity of uniform motion = 5 m /s

time during which there was uniform velocity = 175 / 5 = 35 s

Total time = 5 + 35 + 5 = 45 s .

4 0

3 years ago

6. A satellite is orbiting Earth just above its surface. The centripetal force making the satellite follow a circular trajectory

Svetllana [295]

Answer:

Engular velocity: $w=1,24*10^{-3}/s$

Linear velocity: $V=7905 m/s$

The time it takes:

$t=5060s=84min$

Explanation:

The magnitude of the centripetal acceleration can be related to the angular velocity and radius as:

(1) $a=r*w^{2}$

Solving for w:

(2) $w=\sqrt{\frac{a}{r} }$

Replacing a=9,8m/s2 and r=6,375,000m:

(3) $w=\sqrt{\frac{9,8m/s^{2}}{6375000m} }=1,24*10^{-3}/s$

And the angular velocity relates to the linear velocity:

$V=w*r=1,24*10^{-3}/s*6375000m=7905 m/s$

The perimeter of the orbit is:

$P=\pi *2*r=\pi *2*6375000m=40.05*10^{6}m$

The time it takes:

$t=\frac{P}{V} =\frac{40.05*10^{6}m}{7905 m/s}=5060s=84min$

5 0

3 years ago

Please help i'm going to throw up from stress

Eddi Din [679]

Answer:

Explanation:

First of all, I used the specific heat of water as 4182 J/(kgC) and the specific heat of ethyl alcohol (EtOH) as 2440 J/(kgC); that means that we need the masses in kg, not g.

120.g = .1200 kg of ethyl alcohol. Now for the formula:

$t_f=\frac{(m_{H2O}*spheat_{H2O}*temp_{H2O})+(m_{EtOH}*spheat_{EtOH}*temp_{EtOH})}{(m_{H2O}*spheat_{H2O})+(m_{EtOH}*spheat_{EtOH})}$ where spheat is specific heat.