Answer:
B. They show the pattern made by the magnetic field lines around the
magnets
Explanation:
Using iron fillings, the pattern of the magnetic field lines around a bar magnet can be known.
Magnetic field lines are the line of force around a bar magnet.
- These iron fillings will trace the pattern of the magnetic field around the magnet.
- The domains of the iron fillings begins to align and orient with that of the prevailing magnetic field around.
- Those areas with the strongest force will attract more fillings and those far away will attract lesser fillings.
Answer:
Angular momentum of the system is 4.8 kg m^2/s
Explanation:
As we know that the angular momentum of the system of masses is given as

here we have


now we also know that


now we have


Answer:
43.88 meters per second
Explanation:
The computation of the speed is shown below:
As we know that

where,
Distance is 395,000 meters
Time is 9,000 seconds
Now placing these values to the formula
So, the speed is

= 43.88 meters per second
As speed shows the relation between the distance and time and the same is to be considered i.e by applying the formula
The whistle you use to call has a frequency of 21 kHz, so you do not recognize it also because your threshold of hearing is only 20 kHz. Since you are unable to hear sounds above this value, you request your friend to blow the whistle and move farther away. The frequency will decrease due to Doppler effect.

Distance travelled by the truck is ~
And it's displacement is ~

See the diagram in attachment for reference ~
Let O be the initial point, It travels 60 km towards west till point B and then 80 km towards north till point P and returns to initial point O in a straight line, now as we can observe here, it forms a right angled Triangle.
The measure of two legs is 60 km and 80 km, let's find the hypotenuse ~
According to Pythagoras theorem ~
hypotenuse² = sum of squares of other two legs
that is ~
So, the distance between the point A and O is 100 km
Now, The total distance is equal to the distance covered through actual path that is ~
And displacement is the distance between the final point and initial point, but since the truck returns to the point from where it started the journey, so the final and initial point is same therefore displacement is equal to 0.