A vehicle traveling at a steady speed takes 4 hours to travel 244 km. calculate the average speed of this vehicle.

16. The energy absorbed in 10minutes by an electrical heater is 1.5 MJ. The supply voltage is 240 V. calculate: a) The current d

dsp73

Answer:

If by 1.5 MJ you mean 1.5E6 Joules then

W = P t = power X time

W / t = P power

P = 1.5E6 J / 600 sec = 2500 J / s

P = I V

a) I = 2500 J/s / (240 J/c) = 10.4 C / sec = 10.4 amps

b) Q = I t = 10.4 C / sec * 300 sec = 3120 Coulombs

c) E = P * t = 2500 J / sec * 100 hr * 3600 sec / hr = 9.0E8 Joules

5 0

2 years ago

Three balls, with masses of 3m,2m and m, are fastened to a massless rod of length L. The rotational inertias about the ledt

Oduvanchick [21]

I = MR^2

The Attempt at a Solution:::

I total = (3M)(0)^2 + (2M)(L/2)^2 + (M)(L)^2

I total = 3ML^2/2

It says the answer is 3ML^2/4 though.

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8 0

2 years ago

If a cup of coffee has temperature 95∘C95∘C in a room where the temperature is 20∘C,20∘C, then, according to Newton's Law of Coo

lina2011 [118]

Answer:

T = 76.39°C

Explanation:

given,

coffee cup temperature = 95°C

Room temperature= 20°C

expression

$T( t ) = 20 + 75 e^{\dfrac{-t}{50}}$

temperature at t = 0

$T( 0 ) = 20 + 75 e^{\dfrac{-0}{50}}$

T(0) = 95°C

temperature after half hour of cooling

$T( t ) = 20 + 75 e^{\dfrac{-t}{50}}$

t = 30 minutes

$T( 30 ) = 20 + 75 e^{\dfrac{-30}{50}}$

$T( 30 ) = 20 + 75 \times 0.5488$

T(30) = 61.16° C

average of first half hour will be equal to

$T = \dfrac{1}{30-0}\int_0^30(20 + 75 e^{\dfrac{-t}{50}})\ dt$

$T = \dfrac{1}{30}[(20t - \dfrac{75 e^{\dfrac{-t}{50}}}{\dfrac{1}{50}})]_0^30$

$T = \dfrac{1}{30}[(20t - 3750e^{\dfrac{-t}{50}}]_0^30$

$T = \dfrac{1}{30}[(20\times 30 - 3750 e^{\dfrac{-30}{50}} + 3750]$

$T = \dfrac{1}{30}[600 - 2058.04 + 3750]$

T = 76.39°C

4 0

3 years ago

When would a scientist accept the alternative

vredina [299]

Answer:

B.) if statistical results are significant

Explanation:

If a scientist accepts the null hypothesis, then there is enough evidence to reject the null hypothesis.

This means that the p-value is less than the significance level.

When the scientist accepts the alternative hypothesis, it means the statistical results are significant.

The correct answer is B.

3 0

3 years ago

An acorn falls 10 meters in 4 seconds. What is its average velocity?

quester [9]

Answer:

Average velocity, V = 2.5m/s

Explanation:

Given the following data

Displacement = 10m

Time = 4secs

Average velocity can be defined as the rate of change in displacement with time. Velocity is a vector quantity and as such it has both magnitude and direction.

Mathematically, average velocity is given by the equation;

$Velocity = \frac{displacement}{time}$

$V = \frac{d}{t}$

Substituting into the above equation;

$V = \frac{10}{4}$

Average velocity, V = 2.5m/s

3 0

2 years ago