V. Give reason for the following.
15. Astronomers fail to hear the sound of each other on the surface of the moon.
16. Whales and dolphins are able to communicate.
17. The instrument shown in the picture creates musical sound.
Answers
Answer:
15. Astronauts float around in space because there is no gravity in space. Everyone knows that the farther you get from Earth, the less the gravitational force is. Astronauts are so far from the Earth that gravity is so small. There is no atmosphere in space, therefore propagation of sound is not possible there. Sound needs a material medium for their propagation. In the space, there is no material medium so astronauts cannot listen to each other.
16. Communication amongst whales and dolphins is achieved in several ways. They create sounds, make physical contact and use body language. ... Clicks are used to sense their surroundings through echolocation, while they use whistles to communicate with other members of their species and very likely, with other species too.
17. Where is the picture?
Explanation:
answer 15: Because sound requires a medium to travel since there is nothing in space(vacuum) the sound cannot travel through space.
answer 16: they can transmit ultrasonic sound waves (above 20,000hz , not audible for human) and when these waves strike a surface and echo is produced this let's the dolphins know about the location of the object, also they use different signals like moving tail etc.
17: which picture??