Answer:
a) 30.84m/s
b) 348.32Hz
c) 32.34m/s
d) 289.69Hz
Explanation:
a) If 1 mile=1609,34m, and 1 hour=3600 seconds, then 69mph=69*1609.34m/3600s=30.84m/s
b) Based on Doppler effect:
/*I will take as positive direction the vector
*/


c) 
d) 
Answer: 184,615,384.6 years
Explanation:
This problem can be solve by the following equation:
(1)
Where:
is the spreading rate of the seafloor, its velocity
is the distance the Africa's west coast moved at this rate
is the time it took to the coast to move the descibed distance
Isolating
from (1):
(2)
(3)
Finally:
This is the time it took to the Africa's west coastto move away from the Mid atlantic ridge.
D
Explanation:
The are the same but difference