The average speed of the car is

(the mile marker he passes at the end of the 1.75 h) minus 115
divided by
(1.75 hours) .

The unit is 'miles per hour'.

6 0

3 years ago

A weather balloon is designed to expand to a maximum radius of 21 m at its working altitude, where the air pressure is 0.030 atm

dezoksy [38]

Answer:

7.65 m

Explanation:

$P_1$ = Initial pressure = 0.03 atm

$P_2$ = Final pressure = 1 atm

$r_1$ = Inital radius = 21 m

$V_1$ = Intial volume of gas = $\frac{4}{3}\pi r_1^3$

$V_2$ = Final volume of gas = $\frac{4}{3}\pi r_2^3$

$T_1$ = Initial temperature = 200 K

$T_2$ = Final temperature = 323 K

From ideal gas law we have

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}\\\Rightarrow \frac{P_1\frac{4}{3}\pi r_1^3}{T_1}=\frac{P_2\frac{4}{3}\pi r_2^3}{T_2}\\\Rightarrow \frac{P_1 r_1^3}{T_1}=\frac{P_2r_2^3}{T_2}\\\Rightarrow r_2=\frac{P_1r_1^3T_2}{T_1P_2}\\\Rightarrow r_2=\left(\frac{0.03\times 21^3\times 323}{200\times 1}\right)^{\frac{1}{3}}\\\Rightarrow r_2=7.65\ m$

The radius at liftoff is 7.65 m

7 0

4 years ago

Two satellites have circular orbits with the same radius. Which has a higher speed? One satellite has more mass and the other ha

RideAnS [48]

The satellite with more mass will definitely have a higher speed. The correct option among all the options that are given in the question is the first option. Although the satellite having more mass should have a larger mass difference to have a noticeable speed change. Otherwise it would be hard to detect the speed change. Also we know that
orbit speed = proportional to square root[(Mass of Earth + Mass of Satellite)/orbit radius]. This explains the answer. <span />

3 0

3 years ago

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