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3 years ago

As the train in the image moves to the right which person hears the train horn at a lower pitch?

Physics

2 answers:

Svetach [21]3 years ago

5 0

B. C would be your answer

Margaret [11]3 years ago

5 0

Letter B. (the answer would be c)

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a golf ball is hit with a velocity of 30.0 m/s at an angle of 25 degrees about the horizontal. how long is the ball in the air a

Pie

Ok so use trigonometry to work out the vertical component of velocity.

sin(25) =opp/hyp
rearrange to:
30*sin(25) which equals 12.67ms^-1

now use SUVAT to get the time of flight from the vertical component,

V=U+at

Where V is velocity, U is the initial velocity, a is acceleration due to gravity or g. and t is the time.

rearranges to t= (V+u)/a

plug in some numbers and do some maths and we get 2.583s

this is the total air time of the golf ball.

now we can use Pythagoras to get the horizontal component of velocity.

30^2-12.67^2= 739.29
sqrt739.29 = 27.19ms^-1

and finally speed = distance/time

so--- 27.19ms^-1*2.583s= 70.24m

The ball makes it to the green, and the air time is 2.58s

4 0

3 years ago

A 15-ft3 tank contains oxygen initially at 14.7 psia and 80°F. A paddle wheel within the tank is rotated until the pressure insi

Nikolay [14]

Explanation:

Equation for energy balance will be as follows.

$\Delta E_{system} = E_{in} - E_{out}$

$\Delta U = W_{in} - Q_{out}$

Hence, $W_{in} = Q_{out} + mC_{v} (T_{2} - T_{1})$

Therefore, we will calculate the final temperature as follows.

$\frac{P_{1}V}{T_{1}} = \frac{P_{2}V}{T_{2}}$

$T_{2} = \frac{20 psia}{14.7}(638 R)$

= 868.03 R

Now, we will calculate the mass as follows.

m = $\frac{P_{1}V}{RT_{1}}$

= $\frac{14.7 psia \times 15 ft^{3}}{0.3353 psi ft^{3}/lbm R \times 638 R}$

= 1.031 lbm

Hence,

$W_{in} = Q_{out} + mC_{v} (T_{2} - T_{1})$

Putting the values into the above equation as follows.

$W_{in} = Q_{out} + mC_{v} (T_{2} - T_{1})$

$W_{in} = 20 Btu + 1.031 lbm (\frac{0.160 Btu}{lbm R})(735 - 540)R$

$W_{in}$ = 655.2 Btu

Thus, we can conclude that work done by paddle wheel is 655.2 Btu.

6 0

3 years ago

the resistance of a wire of length 80cm and of uniform area of cross-section 0.025cmsq., is found to be 1.50 ohm. Calculate spec

vivado [14]

$Specific\ resistance\ =resistivity\\
From\ formula\ on \ resistance:\ R= \frac{pL}{A}\ p-resistivity,\ L-length,\\ A-area\ of\ cross\ section\\
p= \frac{R*A}{L}= \frac{1,5Ohm*0,025*10^{-4}m^2 }{80* 10^{-2}m }=0,0003515625 Ohm*m$

3 0

3 years ago

The speed v of a sound wave traveling in a medium that has bulk modulus b and mass density ρ (mass divided by the volume) is v=b

PilotLPTM [1.2K]

As it is given that Bulk modulus and density related to velocity of sound

$v = \sqrt{\frac{B}{\rho}}$

by rearranging the equation we can say

$B = \rho * v^2$

now we need to find the SI unit of Bulk modulus here

we can find it by plug in the units of density and speed here

$B = \frac{kg}{m^3} * (\frac{m}{s})^2$

so SI unit will be

$B = \frac{kg}{m* s^2}$

SO above is the SI unit of bulk Modulus

3 0

3 years ago

For which length of wire are the readings of resistance the most precise

levacccp [35]

The resistance of a wire is directly proportional to the length of the wire. That is the longer the length of the wire, the higher the resistance and the shorter the length of the wire, the smaller the resistance.

7 0

3 years ago