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SpyIntel [72]
2 years ago
6

I need help with questions b and d, that’s all. Thank you.

Physics
1 answer:
Mkey [24]2 years ago
7 0

b).  The power depends on the RATE at which work is done.  

Power = (Work or Energy) / (time)

So to calculate it, you have to know how much work is done AND how much time that takes.

In part (a), you calculated the amount of work it takes to lift the car from the ground to Point-A.  But the question doesn't tell us anywhere how much time that takes.  So there's NO WAY to calculate the power needed to do it.

The more power is used, the faster the car is lifted.  The less power is used, the slower the car creeps up the first hill.  If the people in the car have a lot of time to sit and wait, the car can be dragged from the ground up to Point-A with a very very very small power ... you could do it with a hamster on a treadmill.  That would just take a long time, but it could be done if the power is small enough.

Without knowing the time, we can't calculate the power.

...

d).  Kinetic energy = (1/2) · (mass) · (speed squared)

On the way up, the car stops when it reaches point-A.  

On the way down, the car leaves point-A from "rest".

WHILE it's at point-A, it has <u><em>no speed</em></u>.  So it has no (<em>zero</em>) kinetic energy.

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Can someone help??
Paul [167]

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.

8 0
3 years ago
Which mixtures could be separated using evaporation? Check all that apply. fat in milk salt in ocean water mud in pond water but
salantis [7]
I would go with salt in ocean water as when you heat it and the water begins to evaporate it will leave the salt behind


Also water in mud as the water would evaporate and leave the mud residue behind


GOOD LUCK
BRAINLIEST IF HELPED
5 0
3 years ago
Read 2 more answers
Why is streak generally a more useful property than color in identifying a mineral?
poizon [28]
You may confuse two minerals by their colors so using streak is another way for showing their "true colors "
3 0
3 years ago
In this image of Earth and the Moon from the Sim, what does the circle around Earth represent?
lidiya [134]

Answer: This is the orbit (of the moon around Earth).

An orbit is a circular/oval path that planets, moons, comets, etc follow with a "subject" in the middle. In this case, the circle is the orbit of the moon around Earth.

5 0
3 years ago
A 103 kg horizontal platform is a uniform disk of radius 1.71 m and can rotate about the vertical axis through its center. A 68.
Andreyy89

Answer:

I_{total}=220.64 kg*m^{2}

Explanation:

The moment of inertia of the system is equal to the each population and the platform inertia so

Inertia disk

I_{disk}=\frac{1}{2}*m_{disk}*(r_{p})^{2}

Inertia person

I_{p}=\frac{1}{2}*m_{p}*(r_{p})^{2}

Inertia dog

I_{d}=\frac{1}{2}*m_{d}*(r_{d})^{2}

The Inertia of the system is the sum of each mass taking into account that all exert the force of inertia:

I_{total}=I_{disk}+I_{p}+I_{d}

I_{total}=\frac{1}{2}*103kg*(1.71)^{2}+\frac{1}{2}*68.9kg*(1.09)^{2}+\frac{1}{2}*27.7kg*(1.45)^{2}

I_{total}=220.64 kg*m^{2}

5 0
3 years ago
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