9)
Tommy was walking at a rate of 4
miles
hour
at noon and at 12:30 pm he was walking at a brisk rate of 6
miles
hour
. Two hours later Tommy was walking at a leisurely rate of 2
miles
hour
. Which statement about Tommy's accleration is true?
A) Tommy had an accleration of zero the entire time.
B) Tommy had a positive acceleration between noon and 12:30 pm.
C) Tommy had a positive acceleration between 12:30 and 2:30 pm.
D) Tommy had a negative acceleration between noon and 12:30 pm.

B

Explanation:

At 12 Tommy was walking at 4 mph, then at 12:30 he was walking at 6 mph. He went from 4 to 6 which on a graph would go up, therefore a positive acceleration

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what do the different brain waves do?

explanation:

brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other. brainwaves are detected using sensors placed on the scalp. brainwave speed is measured in hertz (cycles per second) and they are divided into bands delineating slow, moderate, and fast waves.

cell division is not regulated in tumor cells.