Answer: c
Explanation: because if it increases then it gets hotter
if it decreases then its getting colder.
When a helicopter engine spins the main rotor, it generates torque (see How a Helicopter Works), an equal and opposite reaction. Torque makes it so that the engine itself wants to spin.
Answer:
1.An element consists of the same kind of atoms while a compound is composed of different kinds of atoms.
2.A monoatomic element cannot be split up physically or chemically but a compound can be split up into new substances by chemical means.
3.Only limited number of elements are known in an element whiles number of known compounds are quite large.
4.The property of an element is the property of the atom whiles the property of a compound is quite different from that of it's constituents.
5 . Elements are represented by symbols and numbers.for example Sodium is represented by Na whiles compounds are represented by their chemical formula.for example,Salt is represented by the formula NaCl.
Answer:
When a physical change in a sample occurs, composition of the sample does not change. It stays the same. It stays the same. Also, the properties of the sample will still be the same
So, option 3 or the ambulance sound waves have more waves and shorter wavelength is the correct reason for ambulance siren having higher pitch compared to fire truck siren
Explanation:
Pitch of any sound wave is determined as the clarity in frequency of notes or the number of times a cycle is repeated for a single second. So pitch is similar to frequency. And frequency is the measure of number of complete cycles in a second. So if the ambulance siren has higher pitch compared to siren of fire truck. Then this means the frequency of ambulance siren is greater than the fire truck siren. As the frequency is more, then from the given options, choice 3 is correct. The ambulance siren have more waves and shorter wavelength. As more the frequency or number of waves, lesser or shorter is the wavelength of sound wave from ambulance.
