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3 years ago

A car of mass 998 kilograms moving in the positive y–axis at a speed of

Physics

2 answers:

aksik [14]3 years ago

8 0

The total momentum should come out to be 2.0 x 10^4 kilogram meters/second

Hoochie [10]3 years ago

7 0

Answer:

Momentum in X direction = 20400 kg m/s

Explanation:

As we know that there is no external force on this system of two cars

so here the momentum of two cars will remains conserved always

So here we can say that initial total momentum of two cars in Y direction is given as

$P_y = mv_y$

$P_y = 998 (20) = 19960 kg m/s$

Now for X direction total momentum is given as

$P_x = mv_x$

$P_x = 1200(17) = 20400 kg m/s$

so here its momentum in x direction will always remains the same and its final momentum in x direction is given as

$P_x = 20400 kg m/s$

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It is generally seen that, when a substance absorbs heat energy, its heating curve shows two plateaus. Which phenomenon is indic

Tatiana [17]

Answer:

The correct answer is;

Change of phase.

Explanation:

When the physical state in which a substance exists in nature changes to another physical state such as a change from solid state to a liquid stat or from a liquid state to a gaseous state, the substance is said to have undergone a phase change, or phase transformation.

The state of a substance will change, depending on the surrounding temperature and the applied pressure and the energy required for the substance to change its state is known as latent heat.

The observed plateaus are periods the latent heat is absorbed to completely change the phase of the substance.

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3 years ago

An athlete needs to lose weight and decides to do it by “pumping iron.” (a) How many times must an 90.0 kg weight be lifted a di

Wittaler [7]

Answer:

230kg would be the best answer

Explanation:

7 0

3 years ago

How much electrical energy is used by a 75 W laptop that is operating for 12 minutes?

Liono4ka [1.6K]

"1 watt" means 1 joule of energy per second.

75 W means 75 joules/sec .

Energy = (75 Joule/sec) x (12 min) x (60 sec/min)

Energy = (75 x 12 x 60) (Joule-min-sec / sec-min)

Energy = 54,000 Joules

7 0

3 years ago

What is the (magnitude of the) centripetal acceleration (as a multiple of g=9.8~\mathrm{m/s^2}g=9.8 m/s 2 ) towards the Eart

Wittaler [7]

Answer:

The centripetal acceleration as a multiple of $g=9.8 m/s^{2}$ is $1.020x10^{-3}m/s^{2}$

Explanation:

The centripetal acceleration is defined as:

$a = \frac{v^{2}}{r}$ (1)

Where v is the velocity and r is the radius

Since the person is standing in the Earth surfaces, their velocity will be the same of the Earth. That one can be determined by means of the orbital velocity:

$v = \frac{2 \pi r}{T}$ (2)

Where r is the radius and T is the period.

For this case the person is standing at a latitude $71.9^{\circ}$ . Remember that the latitude is given from the equator. The configuration of this system is shown in the image below.

It is necessary to use the radius at the latitude given. That radius can be found by means of trigonometric.

$\cos \theta = \frac{adjacent}{hypotenuse}$

$\cos \theta = \frac{r_{71.9^{\circ}}}{r_{e}}$ (3)

Where $r_{71.9^{\circ}}$ is the radius at the latitude of $71.9^{\circ}$ and $r_{e}$ is the radius at the equator ( $6.37x10^{6}m$ ).

$r_{71.9^{\circ}}$ can be isolated from equation 3:

$r_{71.9^{\circ}} = r_{e} \cos \theta$ (4)

$r_{71.9^{\circ}} = (6.37x10^{6}m) \cos (71.9^{\circ})$

$r_{71.9^{\circ}} = 1.97x10^{6} m$

Then, equation 2 can be used

$v = \frac{2 \pi (1.97x10^{6} m)}{24h}$

Notice that the period is the time that the Earth takes to give a complete revolution (24 hours), this period will be expressed in seconds for a better representation of the velocity.

$T = 24h . \frac{3600s}{1h}$ ⇒ $84600s$

$v = \frac{2 \pi (1.97x10^{6} m)}{84600s}$

$v = 146.31m/s$

Finally, equation 1 can be used:

$a = \frac{(146.31m/s)^{2}}{(1.97x10^{6}m)}$

$a = 0.010m/s^{2}$

Hence, the centripetal acceleration is $0.010m/s^{2}$

To given the centripetal acceleration as a multiple of $g=9.8 m/s^{2}$ it is gotten:

$\frac{0.010m/s^{2}}{9.8 m/s^{2}} = 1.020x10^{-3}m/s^{2}$

6 0

3 years ago

Explain why water, with its high specific heat capacity, is utilized for heating systems such as hot-water radiators.

Lubov Fominskaja [6]

Answer:

Answer in explanation

Explanation:

Water is mainly used as coolant in heating systems like hot-water radiators. The main function of water in such systems, is to absorb as much heat as possible, in order to decrease the temperature of the system and as a result cool it.

The specific heat capacity is the measure of heat energy that is required to raise the temperature of unit mass of a substance through 1 °C. In other words, specific heat capacity quantifies the amount of heat that can be stored by a unit mass of a substance having a degree rise in temperature.

Thus, the more specific heat a substance has, the more heat it can absorb from the hot system. Hence, the specific heat capacity of a coolant must be high.

This is the reason why water, with its high specific heat capacity, is utilized for heating systems, such as radiators.

5 0

3 years ago