A runner is training and runs past meter mark 65 and starts a stopwatch. After the runner passes meter mark 15 the stopwatch stops at 8 seconds. What was the runners velocity?
Question options:
-6.25 m/s
6.25 m/s
8.13 m/s
-1.88 m/s

6.25 m/s

Explanation:

Given parameters

Initial mark = 65

Final mark  = 15

time taken = 8s

Unknown:

Velocity of the runner  = ?

Solution:

Velocity is the displacement divided by time;

        Velocity  =  

Displacement  = Initial mark - final mark  = 65 - 15 = 50m

Now, insert the parameters and solve;

       Velocity  =   = 6.25m/s

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j