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3 years ago

An object is 45 m above the ground when it is dropped. How fast is the object going just before it hits the ground?

1 answer:

3 0

This is a kinematics question.
$v^{2} = v_{0} ^{2} + 2g(y - y_{0}) \\ 
v^{2} = 0 + 2(-9.8)(0 - 45) \\ 
v^{2} = 882 \\ v = \sqrt{882} = 29.7 m/s$

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If the body's temperature is above 105 °F for a prolonged period, heat stroke

seraphim [82]

Answer:

Explanation:

C = (F-32)*5/9 = 73*5/9 = 40.55555

since the answers are spread apart, technically you can just estimate by doing -32

and then /2

since 5/9 is close to 1/2

7 0

3 years ago

Determine the length of the tungsten filament in a 100 watt lightbulb given: (i) the resistivity of tungsten is 5.6 × 10−8 Ω · m

svetoff [14.1K]

Answer:

0.34148 m

Explanation:

$\rho$ = Resistivity of tungsten = $5.6\times 10^{-8}\ \Omega m$

d = Diameter = 0.0018 inch

r = Radius = $\dfrac{r}{2}=\dfrac{0.0018}{2}=0.0009\ in$

$r=0.0009\times 0.0254=0.00002286\ m$

$\alpha$ = Temperature coefficient of tungsten = $0.0045 /^{\circ}C$

Power is given by

$P=\dfrac{V^2}{R}\\\Rightarrow R=\dfrac{V^2}{P}\\\Rightarrow R=\dfrac{120^2}{100}\\\Rightarrow R=144\ \Omega$

We have the equation

$R_2=R_1[1+\alpha(T_2-T_1)]\\\Rightarrow R_1=\dfrac{R_2}{1+\alpha(T_2-T_1)}\\\Rightarrow R_1=\dfrac{144}{1+0.0045(2550-25)}\\\Rightarrow R_1=11.64812\ \Omega$

Resistance is given by

$R=\rho\dfrac{l}{A}\\\Rightarrow l=\dfrac{RA}{\rho}\\\Rightarrow l=\dfrac{11.64812\times \pi (0.00002286)^2}{5.6\times 10^{-8}}\\\Rightarrow l=0.34148\ m$

The length of the filament is 0.34148 m

7 0

3 years ago

Find the distance from a point charge q=100nC where the field intensity is equal to E=6kN/C. please include description of the r

madam [21]

Answer: 0.3872m

Explanation:

q= 100nC --> 100x10^-9 C

k= 9x10^9 Nm^2/C^2

E= 6kN/C --> 600 N/C

r=?

$E= K\frac{q}{r^{2} }$ --> $r=\sqrt{\frac{kq}{E} }$ Despejas "r"

Resuelves

<h3> $r=\sqrt{\frac{(9x10^9 Nm^2/C^2)(100x10x^{-9} C)}{6000N/C} }$ (la x es por, no es una variable)</h3><h3>r= 0.3872983346m</h3>

4 0

3 years ago

What is the result of two displacement vectors having opposite directions?

jonny [76]

<u>Answer:</u>

<em>Resultant of two vectors having opposite direction is the difference of the two displacements having the same direction as the larger vector. </em>

<u>Explanation:</u><u> </u>

Resultant of two vectors is obtained by performing the vector addition operation. When the directions of both vectors are same the resultant’s direction will also be the same as the inputs. When two vectors have opposite directions, one direction will be taken positive making one vector positive and the other negative.

By performing addition of a positive and negative number we are actually taking the difference between both. Thus performing vector addition of two vectors with opposite directions is equivalent to finding the difference between the vectors. Consider a system consisting of a solid block, on which two forces F1 and F2 act in the opposite direction.

One force will be considered positive and the other is considered negative. The resultant is given by the difference of two force vectors. Displacement of the block will be in the direction of the greater force.

5 0

3 years ago

Read 2 more answers

A man supports himself and the uniform horizontal beam pulling the rope with a force T.The weights of men and the beam are 883 N

artcher [175]

Answer:

T=502.5N

Ax=171.8N

Explanation:

The computation of the tension T in the rope and the forces exerted by the pin at A is shown below:

vertical forces sum = Ay + Tsin20 + T - 245 - 883 = 0

Now

horizontal forces sum = Ax - Tcos70

Now Moment about B

-Ay × 4.8 + 245 × 2.4 + 883 × 1.8=0

Ay=453.6N

Now substitute in sum of vertical forces T=502.5N

Ax=171.8N

3 0

3 years ago