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4 years ago

A train travels 94 kilometers in 3 hours, and then 65 kilometers in 3 hours. What is its average speed?

Physics

2 answers:

Norma-Jean [14]4 years ago

8 0

The average speed of the train is about 26.5 kilometers per hour

const2013 [10]4 years ago

6 0

Average speed =

(total distance covered) / (total time to cover the distance) .

Total distance covered = (94km + 65 km) = 159 km.

Total time = (3 hr + 3 hr) = 6 hours

Average speed = (159 km) / (6 hours) = 26.5 km/hr .

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A machine has a mechanical advantage of 5. what force should be applied to the machine to make it apply 30000

FrozenT [24]

Answer:

6000

Explanation:

E=Effort MA=mechanical advantage

L=Load

MA=L/E

5=30000/E

5E=30000

E=6000N

4 0

3 years ago

Read 2 more answers

Two objects are connected by a string that passes over a frictionless pulley as in the figure below, where m1 < m2 and a1 and

Lady_Fox [76]

Answer:2

Explanation:

Given

$m_2>m_1$

and $a_1$ and $a_2$ are the acceleration of 1 and 2

Suppose T is the Tension

then for block 2

$m_2g-T=m_2a$

$m_2(g-a)=T---1$

For block 1

$T-m_1g=m_1a$

$T=m_1(g+a)----2$

equate 1 and 2

$m_2(g-a)=m_1(g+a)$

$a=\frac{m_2-m_1}{m_1+m_2}$

where $a=a_1=a_2$

thus we can see that a is less than g

therefore $a_2 < g$

4 0

3 years ago

La aceleración de un proyectil que describe una trayectoria parabólica cerca de la superficie terrestre es constante o variable

Ann [662]

Answer:

Es una constante porque sigue funcionando y debido a la gravedad, tú tendrías que ser tú quien la detenga si está bajando en lugar de hacia arriba.

Explanation:

5 0

3 years ago

George determines the mass of his evaporating dish to be 3.375 g. He adds a solid sample to the evaporating dish, and the mass o

zhannawk [14.2K]

Explanation:

The given data is as follows.

Mass of evaporating dish = 3.375 g

Total mass = Mass of solid sample + evaporating dish

That is, Mass of solid sample + evaporating dish = 26.719 g

Therefore, we will calculate the mass of solid sample as follows.

Mass of solid sample = (Mass of solid sample + evaporating dish) - mass of evaporating dish

= 26.719 g – 3.375 g

= 23.344 g

Thus, we can conclude that mass of his solid sample must be 23.344 g.

3 0

4 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

3 years ago