isotopes are the same element, but have different numbers of neutrons (but still have the same number of electrons and protons), hence have a different mass number.
Answer:
The frequency of sound heard by the boy is 1181 Hz.
Explanation:
Given that,
Frequency of sound from alarm 
Speed = -8.25 m/s
Negative sign show the boy riding away from the car
Speed of sound = 343
We need to calculate the heard frequency
Using formula of frequency

Where,
= frequency of source
= speed of observer
= speed of source
= speed of sound
Put the value into the formula

here, source is at rest


Hence, The frequency of sound heard by the boy is 1181 Hz.
The earth all the way around is 196.9 million miles
Answer:
Taking water and oxygen from Earth is rather expensive and hard to do.
Explanation:
Without water and oxygen, travel to other planets is basically impossible