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storchak [24]
3 years ago
10

You leave the doctor's office after your annual checkup and recall that you weighed 689 N in her office. You then get into an el

evator that, conveniently, has a scale. Find the magnitude and direction of the elevator's acceleration if the scale reads
Physics
1 answer:
son4ous [18]3 years ago
8 0

Answer: 0.455 m/s^2

Explanation:

f = ma = m x 9.8=689 (the mass is constant)

m = 78.3

now on the elevator

f = 721 = m x a

a= 10.26

the elevator is moving down because there is a increase in weight. the acceleration of elevator = 10.26-9.8 = 0.455

You might be interested in
How much energy is needed to melt 5 g of ice? The specific latent heat of melting for water is 334000 J/kg.
Katen [24]

Answer:

The needed energy to melt of ice is 1670 J.

Explanation:

Given that,

Mass of ice = 5 g

Specific latent heat = 334000 J/kg

We need to calculate the energy

Using formula of energy

Q=mL

Where, m = mass

L = latent heat

Put the value into the formula

Q=5\times10^{-3}\times334000

Q=1670\ J

Hence, The needed energy to melt of ice is 1670 J.

5 0
3 years ago
A very long insulating cylinder has radius R and carries positive charge distributed throughout its volume. The charge distribut
blsea [12.9K]

Answer:

1.E(r) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R})

2.E(r) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r}

3.The results from part 1 and 2 agree when r = R.

Explanation:

The volume charge density is given as

\rho (r) = \alpha (1-\frac{r}{R})

We will investigate this question in two parts. First r < R, then r > R. We will show that at r = R, the solutions to both parts are equal to each other.

1. Since the cylinder is very long, Gauss’ Law can be applied.

\int {\vec{E}} \, d\vec{a} = \frac{Q_{enc}}{\epsilon_0}

The enclosed charge can be found by integrating the volume charge density over the inner cylinder enclosed by the imaginary Gaussian surface with radius ‘r’. The integration of E-field in the left-hand side of the Gauss’ Law is not needed, since E is constant at the chosen imaginary Gaussian surface, and the area integral is

\int\, da = 2\pi r h

where ‘h’ is the length of the imaginary Gaussian surface.

Q_{enc} = \int\limits^r_0 {\rho(r)h} \, dr = \alpha h \int\limits^r_0 {(1-r/R)} \, dr = \alpha h (r - \frac{r^2}{2R})\left \{ {{r=r} \atop {r=0}} \right. = \alpha h (\frac{2Rr - r^2}{2R})\\E2\pi rh = \alpha h \frac{2Rr - r^2}{2R\epsilon_0}\\E(r) = \alpha \frac{2R - r}{4\pi \epsilon_0 R}\\E(r) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R})

2. For r> R, the total charge of the enclosed cylinder is equal to the total charge of the cylinder. So,

Q_{enc} = \int\limits^R_0 {\rho(r)h} \, dr = \alpha \int\limits^R_0 {(1-r/R)h} \, dr = \alpha h(r - \frac{r^2}{2R})\left \{ {{r=R} \atop {r=0}} \right. = \alpha h(R - \frac{R^2}{2R}) = \alpha h\frac{R}{2} \\E2\pi rh = \frac{\alpha Rh}{2\epsilon_0}\\E(r) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r}

3. At the boundary where r = R:

E(r=R) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R}) = \frac{\alpha}{4\pi \epsilon_0}\\E(r=R) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r} = \frac{\alpha}{4\pi \epsilon_0}

As can be seen from above, two E-field values are equal as predicted.

4 0
3 years ago
A 200-N woman is standing on a concrete floor. How much force does the floor exert on her?
lisov135 [29]
C.........................
6 0
3 years ago
What is hooke's law? does it apply to elastic materials or to inelastic materials?
zysi [14]
When you talk about Hooke's law, it always have to do something with springs. Hooke's Law, from Robert Hooke, saw a relation between the force applied to the spring and the extension of its length. The equation is: F = kx, where k is the spring constant and x is the displacement of the original and stretched lengths. In other words, x is the length of deformation. Hence, the object must be elastic to come up with a displacement or deformation, in the first place. Then, the Hooke's Law is only applicable to elastic materials.
6 0
3 years ago
All forces are different each exerts a particular type of effect on an object
prisoha [69]
Is this a true and false question?
7 0
3 years ago
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