When she starts out, he is (40x2.5)= 100 miles ahead of her.
She gains (65-40)= 25 miles on him every hour.
It takes her (100/25)= 4 hours to catch up to him.
Answer:
D. Burning paper
Explanation:
physical change is just changing the way it looks
chemical change is changing the properties of the object or thing
melting ice is just changing the way it looks it still has the same atoms and elements.
when you burn something it will change the properties of the atoms in the object
The pain was triggered by the Nervous System
Answer:
The frequency of these waves is 
Explanation:
Given that,
Wavelength = 6.6 km
Distance = 8810 km
Time t = 8.67 hr
We need to calculate the velocity of sound
Using formula of velocity

Where, D = distance
T = time
Put the value into the formula


We need to calculate the frequency
Using formula of frequency


Put the value into the formula





Hence, The frequency of these waves is 