Answer to Question #160198 in Physics for Smayya Ruganyira

Question

 (a)If the speed of a particle is doubled, what happens to its kinetic energy?       (b) What can be said about the speed of a particle if the net work done on it is zero?

A gas of volume 84cm3 is compressed gradually at constant temperature until its pressure rises from 75cm of Mercury to 140cm of mercury. Find the final volume of the gas.

balloon contains 7.2 L of He. The pressure is reduced to 2.00 atm and the balloon expands to occupy a volume of 25.1 L. What was the initial pressure exerted on the balloon?

A fixed mass of gas at constant pressure has a volume of 100cm3 at 27°C. Find its volume at temperature of 54°C.

A sample of oxygen occupies a volume of 160L at 91° C. What will be volume of oxygen when the temperature drops to 0.00° C?

A fixed mass of gas exerts a pressure of 76cm of mercury at 270C.(a)Find the pressure exerted by it at 1000C.(b)State two physical properties of the gas assumed constant.

The pressure in an automobile tire is 1.88 atm at 25.0°C. What will be the pressure if the temperature warms up to 37.0°C?

Calculate the density in g/L of 478 mL of krypton at 47° C and 671 mm Hg.

If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 liters, what is the temperature?

If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87 0C, how many moles of gas do I have?

Describe what is meant by the term magnetic field.

Use words and pictures of explain why permanent magnets have a magnetic field around them. Refer to domain in your explanation.

A magnet attracts a piece of iron. The iron can then attract another piece of iron. On the basis of domain alignment, explain .

What happens in each piece of iron .

What happens to the pole of a magnet if it is cut into pieces .

What happens when like magnetic poles are brought close together .

Explain how a compass indicates the direction of a magnetic field .

Give examples of phenomena that are affected by earth's magnetic field.

Draw a diagram showing the magnetic field around the earth.

Answer 1

(a) If the speed of a particle is doubled, its kinetic energy increases four times.

(b) If the net work done on a particle is zero, its velocity does not change.

The final volume of the gas:

$$V_f=V_i\frac{p_i}{p_f}=45\text{ cm}^3.$$

The initial pressure exerted on the balloon:

$$p_i=p_f\frac{V_f}{V_i}=6.97\text{ atm}.$$

Its volume at temperature of 54°C:

$$V_f=V_i\frac{T_f}{T_i}=109\text{ cm}^3.$$

The volume of oxygen when the temperature drops to 0.00° C will be

$$V_f=V_i\frac{T_f}{T_i}=120\text{ L}.$$

(a) Find the pressure exerted by the gas at 1000 C:

$$p_f=p_i\frac{T_f}{T_i}=178.2\text{ cm}.$$

(b) State two physical properties of the gas assumed constant: mass, volume.

If the temperature warms up to 37.0°C, the pressure will be

$$p_f=p_i\frac{T_f}{T_i}=1.96\text{ atm}.$$

The density of krypton:

$$\rho=\frac{\Mu p}{RT}=2.82\cdot10^{-3}\text{ kg/L}.$$

The temperature:

$$T=\frac{pV}{nR}=204\text{ K}.$$

How many moles:

$$n=\frac{pV}{RT}=1.26\text{ mol}.$$

Magnetic field: a field created by permanent magnets or currents changing with time

Permanent magnets have similarly oriented domains and thus create magnetic field.

Each piece of iron aligns according to the field.

Each pole becomes a smaller magnet.

They repel.

The needle aligns according to the field created by the planet.

Aurora borealis, radio noise from space.