Answer:
a) 30.82 m/s
b) 183.33 Hz
Explanation:
a)
V = speed of the sound = 339 m/s
v = speed of the train = ?
f' = observed frequency by the observer = 220 Hz
f = actual frequency of the observer = 200 Hz
using the equation
v = 30.82 m/s
b)
V = speed of the sound = 339 m/s
v = speed of the train = 30.82 m/s
f'' = observed frequency by the observer as train moves away = ?
f = actual frequency of the observer = 200 Hz
using the equation
f'' = 183.33 Hz
Answer:
From the given options, the option (D) is correct. Because Al is the aluminium which is located in period 3 of the periodic table.
Explanation:
We know that the 3rd period contains 8 elements which are as follows:
- sodium
- magnesium
- aluminium
- silicon
- phosphorus
- sulfur
- chlorine, and
- argon
The sodium and magnesium, the first 2 elements, are members of the s-block of the periodic table, while the rest of the members are the elements of the p-block.
Thus, from the given options, the option (D) is correct. Because Al is the aluminium which is located in period 3 of the periodic table.
Answer:
Energy absorbed or hidden when water evaporates
Explanation:
The heat that is required to make a phase change is known as latent heat.
A phase change occurs when matter changes state. For example from solid to liquid, from liquid to gas, among others.
When changing from liquid to gas (for example when water evaporates), the heat necessary for this to happen is called latent heat of vaporization. The word latent means hidden, because a change in temperature is not perceived during the phase change, even when heat is being added, thus it is said that the heat is hidden or latent.
So the answer is:
- Energy absorbed or hidden when water evaporates.
*Another type of latent heat is the latent heat of fusion, which is when a solid becomes liquid.
Displacement = distance and direction from the start-point
to the end-point, regardless of the route followed on the way.
From the throw to the 'plop', the displacement is 5 meters down.
Answer:
Mass
Explanation:
The mass of an object expresses the amount of matter it comprises. Which implies that objects with higher mass contains higher matter compared to objects with lesser masses. Thereby it determines the measure of inertia experienced by an object when a force is applied to change its direction of motion, or to set it in motion when at rest, or bring it to rest when in motion.
The mass of an object the same no matter its location, and it is measured in kilograms.
