A boy is standing in the middle of a field when his friend sprints past him with a speed of 4 m/s. At the moment his friend passes him, he starts running with an acceleration of 0.8 m/s2. 1. How long will it take him to catch his friend?

2. How far will he have to run?

3. How fast will he be going?

Explanation:

1)  ½(0.8)t² = 4t

        0.4t² = 4t

         0.4t = 4

              t = 10 s

2)           d = vt = 4(10) = 40 m

d =  ½atⁿ = ½(0.8)10² = 40 m

3)    v = at = 0.8(10) = 8 m/s

energy stored in the capacitor= 9.72 x 10⁻⁴ j

explanation:

the energy stored in the capacitor is given by

e= 1/2 c v²

e= energy stored

c= capacitance= 1.5 µc= 1.5 x 10⁻⁶f

v= potential difference=36 v

so energy stored= e= 1/2 (1.5 x 10⁻⁶) (36)²

energy stored= 9.72 x 10⁻⁴j