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monitta
4 years ago
7

A runner increases her speed from 8.9 m/s to 18.3 m/s in 8 seconds. What is the acceleration of the runner

Physics
1 answer:
IgorLugansk [536]4 years ago
3 0
1.25m/s'2 by the first eq of motion
see the steps below
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Neutrons incident on a heavy nucleus with spin J 0 show a resonance at an incident energy ER = 250 eV in the total cross-section
ivolga24 [154]

Answer:

elastic partial width is 2.49 eV

Explanation:

given data

ER  E = 250 eV

spin J = 0

cross-section magnitude σ = 1300 barns

peak P = 20ev

to find out

elastic partial width W

solution

we know here that

σ = λ²× W /  ( E × π × P )     ...................1

put here all value

σ = (0.286)² × W  × 10^{-16}/  ( 250 × π × 20 )

1300 × 10^{-24} = (0.286)² × W  × 10^{-16}/  ( 250 × π × 20 )

solve it and we get W

W = 249.56 × 10^{-2}

so elastic partial width is 2.49 eV

8 0
4 years ago
A point charge of -4.28 pC is fixed on the y-axis, 2.79 mm from the origin. What is the electric field produced by this charge a
makkiz [27]

Answer:

E = (-3.61^i+1.02^j) N/C

magnitude E = 3.75N/C

Explanation:

In order to calculate the electric field at the point P, you use the following formula, which takes into account the components of the electric field vector:

\vec{E}=-k\frac{q}{r^2}cos\theta\ \hat{i}+k\frac{q}{r^2}sin\theta\ \hat{j}\\\\\vec{E}=k\frac{q^2}{r}[-cos\theta\ \hat{i}+sin\theta\ \hat{j}]              (1)

Where the minus sign means that the electric field point to the charge.

k: Coulomb's constant = 8.98*10^9Nm^2/C^2

q = -4.28 pC = -4.28*10^-12C

r: distance to the charge from the point P

The point P is at the point (0,9.83mm)

θ: angle between the electric field vector and the x-axis

The angle is calculated as follow:

\theta=tan^{-1}(\frac{2.79mm}{9.83mm})=74.15\°

The distance r is:

r=\sqrt{(2.79mm)^2+(9.83mm)^2}=10.21mm=10.21*10^{-3}m

You replace the values of all parameters in the equation (1):

\vec{E}=(8.98*10^9Nm^2/C^2)\frac{4.28*10^{-12}C}{(10.21*10^{-3}m)}[-cos(15.84\°)\hat{i}+sin(15.84\°)\hat{j}]\\\\\vec{E}=(-3.61\hat{i}+1.02\hat{j})\frac{N}{C}\\\\|\vec{E}|=\sqrt{(3.61)^2+(1.02)^2}\frac{N}{C}=3.75\frac{N}{C}

The electric field is E = (-3.61^i+1.02^j) N/C with a a magnitude of 3.75N/C

8 0
3 years ago
An object is placed exactly halfway between the Earth and moon. The object will fall toward the
Veronika [31]
Earth as the earth has a higher mass and therefore a higher gravitational force upon the object.
5 0
3 years ago
Read 2 more answers
Which type of ladder has flat steps, hinged back, self-supporting, and non-adjustable?
il63 [147K]

Answer:  Step Ladders

In general ladders are with inclined or vertical set of steps or rungs between two upright lengths of metal or wood. Ladders used for climbing up and down.

<u>Step ladders :</u>

It is a self supporting portable ladder, most commonly used in industries.  Self-supporting means it does not need any support to lean.  So this ladder can be used any where in the rooms. For example middle of the room  where support is not available. Also this ladder is non-adjustable flat steps and hinged back.  

5 0
3 years ago
If this were a theoretical frictionless plane, what would be the mechanical advantage?
alex41 [277]
Mechanical advantage (MA = slope/height)
here length of slope = 9Hheight = H                                                 so mechanical advantage = ---- 9H/H= 9                                                  
3 0
3 years ago
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