Ask question

Ask question

All categories

2 years ago

11

A 5kg block of iron is heated to 800degree C.it is placed in a tub containing 2litre of water at 15degree C.Assuming all the wat

er is brought to the boil rapidly calculate the mass of water which boile off.

1 answer:

icang [17]2 years ago

6 0

Te correct answer is a

You might be interested in

An electron in an unknown energy level of a hydrogen atom transitions to the n=2 level and emits a photon with wavelength 410 nm

lyudmila [28]

Answer:

The initial energy level = 6

Explanation:

Photon wavelength is proportional to energy. The wavelength of emitted photons is related to the energy levels of the atom as given by the Rydberg formula:

ₕ₁₂

(1/λ) = Rₕ [(1/n₂²) − (1/n₁²)]

where n₂ = final energy level = 2

n₁ = initial energy level = ?

Rₕ = Rydberg's constant = 1.097 × 10⁷ m⁻¹

λ = wavelength = 410 nm = 410 × 10⁻⁹ m

1/(410 × 10⁻⁹) = (1.097 × 10⁷) [(1/2²) − (1/n₁²)]

0.223 = [(1/4) − (1/n₁²)]

(1/n₁²) = 0.02778

n₁² = 1/0.02778 = 36

n₁ = 6.

7 0

3 years ago

A student says that a speed of 50 m/s is faster than a speed of 140 km/h because the number is bigger. What would you say to the

ladessa [460]

The units are not consistent - 1 m/s is not the same as 1 km/h.

First thing to do would be to convert from one unit of speed to the other, say km/h to m/s. There are 1000 meters (m) for every kilometer (km) and 3600 seconds (s) for every hour (h), so

$1\,\dfrac{\mathrm{km}}{\mathrm h}\cdot\dfrac{10^3\,\mathrm m}{\mathrm{km}}\cdot\dfrac{\mathrm h}{3600\,\mathrm s}\approx0.278\,\dfrac{\mathrm m}{\mathrm s}$

So in fact 1 km/h is about 4 times slower than 1 m/s.

4 0

2 years ago

Before beginning a long trip on a hot day, a driver inflates anautomobile tire to a gauge pressure of 2.70 atm at 300 K. At the

anygoal [31]

Answer:

The value is the temperature of the air inside the tire $T_{2} =$ 340.54 K

% of the original mass of air in the tire should be released 99.706 %

Explanation:

Initial gauge pressure = 2.7 atm

Absolute pressure at inlet $P_{1}$ = 2.7 + 1 = 3.7 atm

Absolute pressure at outlet $P_{2}$ = 3.2 + 1 = 4.2 atm

Temperature at inlet $T_{1}$ = 300 K

(a) Volume of the system is constant so pressure is directly proportional to the temperature.

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

$\frac{T_{2} }{300} = \frac{4.2}{3.7}$

$T_{2} =$ 340.54 K

This is the value is the temperature of the air inside the tire

(b). Since volume of the tyre is constant & pressure reaches the original value.

From ideal gas equation P V = m R T

Since P , V & R is constant. So

m T = constant

$m_{1} T_{1} = m_{2} T_{2}$

$\frac{m_{2} }{m_{1} } = \frac{T_{1} }{T_{2} }$

$\frac{m_{2} }{m_{1} } = \frac{300}{354.54}$

$\frac{m_{2} }{m_{1} } =0.00294$

value of the original mass of air in the tire should be released is $\frac{m_{2} - m_{1}}{m_{1}}$

$\frac{0.00294-1}{1}$

⇒ -0.99706

% of the original mass of air in the tire should be released 99.706 %.

8 0

2 years ago

Is Fahrenheit an SI unit?

AVprozaik [17]

Answer:

No

Explanation:

Because the people put in charge of defining SI units said so

5 0

2 years ago

A civil engineer plans to design a curved ramp such that a car may not have to rely on friction to round the curve without skidd

Delicious77 [7]

Answer: $\theta =\tan ^{-1}(\frac{v^2}{gR})$

Explanation:

let \theta be the inclination at which curve is tilted

v is the speed of car and R is the radius of curve

m is the mass of car

Suppose R is the reaction offered by road to car

Resolving R in x and y direction we get

$R\cos \theta$ will balance weight and $R\sin \theta$ will provide the necessary centripetal Force

thus $R\sin \theta =\frac{mv^2}{R}$ ------------1

$R\cos \theta =m g$ ----------------2

Divide 1 & 2 we get

$\frac{R\sin \theta }{R\cos \theta }=\frac{mv^2}{mgR}$

$\tan \theta =\frac{v^2}{gR}$

$\theta =\tan ^{-1}(\frac{v^2}{gR})$

8 0

2 years ago