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2 years ago

A man in a lift is moving upwards in a constant speed.the weight of the man is W.Acc

Physics

1 answer:

Nookie1986 [14]2 years ago

3 0

Answer:

Normal force=mg

Explanation:

The reaction force of weight is the normal force.

in order to find the normal for we need to write all the forces and set it equal to the net force:

N-mg=ma (since it is a constant speed the a=0)

N=mg

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At the top of a pole vault, an athlete actually can do work pushing on the pole before releasing it. Suppose the pushing force t

Salsk061 [2.6K]

Answer:

The work done on the athlete is approximately 2.09 J

Explanation:

From the definition of the work done by a variable force:

$\displaystyle{\int_{x_i}^{x_j}F(x)dx}$

and substituting with the function of our problem:

$\displaystyle{\int_{0}^{0.19}(140x-190x^2)dx\approx2.09\mathrm{J}}$

5 0

3 years ago

It takes 130 J of work to compress a certain spring 0.10m. (a) What is the force constant of this spring? (b) To compress the sp

Ede4ka [16]

Explanation:

Given that,

Work done to stretch the spring, W = 130 J

Distance, x = 0.1 m

(a) We know that work done in stretching the spring is as follows :

$W=\dfrac{1}{2}kx^2\\\\k=\dfrac{2W}{x^2}\\\\k=\dfrac{2\times 130}{(0.1)^2}\\\\k=26000\ N/m$

(b) If additional distance is 0.1 m i.e. x = 0.1 + 0.1 = 0.2 m

So,

$W=\dfrac{1}{2}kx^2\\\\W=\dfrac{1}{2}\times 26000\times 0.2^2\\\\W=520\ J$

So, the new work is more than 130 J.

6 0

2 years ago

what would happen to the size of the shadow if the distance between the light and the hand is increased.

Sergio039 [100]

I don’t think I will have any time to go

8 0

2 years ago

Please someone help me? if you have a good answer I will gave U a brainlest :)

Natali5045456 [20]

Answer:

for one its photo

Explanation: answers

this is easy 1. im not sure

2. erosion

3. is deposition

sorry i cant answer all of them but some simple ones deposition is when that stuff is getting moved, erosion is the breaking down of sokething and weathering is weather such as rain acid rain ice etc weather breeakin down rocks etc

6 0

2 years ago

How much heat is needed to raise the temperature of 8g of water by 15oC?

Murrr4er [49]

<h2>Answer: 502.08 J</h2>

Explanation:

The heat (thermal energy) needed in to raise the temperature in a process can be found using the following equation:

$Q=m.C.\Delta T$ (1)

Where:

$Q$ is the heat

$m=8 g$ is the mass of the element (<u>water</u> in this case)

$C$ is the specific heat capacity of the material. In the case of water is $C=4.184\frac{J}{g\°C}$

$\Delta T=15\°C$ is the variation in temperature <u>(which is increased in this case)</u>

Knowing this, let's rewrite (1) with these values:

$Q=(8 g)(4.184\frac{J}{g\°C})(15\°C)$ (2)

Finally:

$Q=502.08 J$

5 0

3 years ago