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)Tommy had a positive acceleration between noon and 12:30 pm.

Explanation:

Acceleration is defined as the rate of change of velocity:

where

v is the final velocity

u is the initial velocity

t is the time

In the problem,

- At noon, Tommy is walking at a velocity of 4 mi/h

- At 12.30 pm, Tommy is walking at a velocity of 6 mi/h

- A time of half an hour (0.5 h) passed between the two moments

So Tommy's acceleration is

and the acceleration is positive, since the velocity has increased.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

no. dot product   =0 when vecs at right angles