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2 years ago

A bus travels 30km in 1/2h. What is it's average speed in km/h

1 answer:

5 0

If a bus travels 30 km in 1/2 hr, then in one hr, he can travel twice the distance.
30*2=60 km

Final answer: 60 km per hr

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Students want to investigate the inverse relationship between the pressure and temperature of an ideal gas as predicted by the i

grin007 [14]

Answer:

Option B, Fix the piston in place so the volume of the pas remains constant

Explanation:

As we know

$\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$

The effect on variable due to another variable can be studied by keeping the third variable constant.

Hence, in order the study the variation of temperature with pressure or vice versa, the volume needs to fixed at a certain value.

Hence, option B is correct

7 0

2 years ago

The resistivity of a metal increases slightly with increased temperature. This can be expressed as rho= rho0[1+α(T−T0)] , where

Stolb23 [73]

Answer:

At 81. 52 Deg C its resistance will be 0.31 Ω.

Explanation:

The resistance of wire = $R_T =\frac{\rho_T \ l}{A}$

Where $R_T$ =Resistance of wire at Temperature T

$\rho_T$ = Resistivity at temperature T $=\rho_0 \ [1 \ + \alpha\ (T-T_0\ )]$

Where $T_0 =20\ Deg\ C , \ \rho_0 = Constant, \alpha =3.9 \times 10^-^3 DegC^-1 \ (Given)$

l=Length of the wire

& A = Area of cross section of wire

For long and thin wire the resistance & resistivity relation will be as follows

$\frac{R_T_1}{R_T_2}=\frac{\rho_0(1+\alpha \cdot(T_1-2 0 )}{\rho_0(1+\alpha \cdot (T_2 -20 )}$

$\frac{0.25}{0.31}=\frac{1}{[1+\alpha(T-20)]}$

$1.24=1+\alpha (T-20)$

$0.24=\alpha(\ T -20 )$

$Putting\ the\ value\ of \alpha = 3.9 \times 10^-^3 DegC^-1$

T = 81.52 Deg C

4 0

2 years ago

~ is the following statement true or false? Explain your answer.

USPshnik [31]

Answer: False

Explanation: The sun is one of earths primary energy sources. Without the sun, all animals, plants, humans would die. The sun's energy provides warmth for humans and plants and animals cannot grow without the sun.

7 0

2 years ago

Which of the Materials are insulators? (select all that apply)

DENIUS [597]

I believe all the insulators would be glass, wood, plastic, and yarn.

But I’m not entirely sure if mechanical pencil lead is an insulator or conductor.

Hope this helps.

3 0

3 years ago

(1 point) A pilot flies in a straight path for 1 hour and 30 min. She then makes a course correction, heading 10 degrees to the

kati45 [8]

Answer:

The pilot is 2214.22 miles from her starting position

Explanation:

Since the pilot is traveling at a constant speed of 635 mph, the total distance traveled can be easily found as follows:

$1stleg: d_{1} = 1.5*635 = 952.5 mi\\2ndleg: d_{2} = 2*635 = 1270 mi$

There was a 10 degrees deviation, so the angle between the trajectory of both legs is 170 degrees.

The distance we need to find is that from the start of the first leg to the end of the second leg, those three distances form a triangle and since the side we're interested in is opposite to the 170 degrees angle, we can determine its length by the law of cosines:

$d_{3}^{2} =d_{1}^{2} + d_{2}^{2} -2*d_{1}*d_{2}*cos(170)\\d_{3}^{2} =952.5^{2} + 1270^{2} -2*952.5*1270*cos(170)\\d_{3}=2214.22mi$

The pilot is 2214.22 miles from her starting position

8 0

2 years ago