Answer:
(a) 8 V, (b) 144000 V, (c) 2 x 10^(-8) C
Explanation:
(a) charge, q = 5 μC , Work, W = 40 x 10-^(-6) J
The electric potential is given by
W = q V

(b)
charge, q = 8 x 10^(-6) C, distance, r = 50 cm = 0.5 m
Let the potential is V.

(c)
Work, W = 8 x 10^(-5) J, Potential difference, V = 4000 V
Let the charge is q.
W= q V

Explanation:
https://educationalghana.news.blog/2021/08/09/geography-human-physical-and-practical-for-wassce-novdec-candidates/
F=ma
Therefore the net force = 1000kg × 2 metres per second per second
So F=2000 N
1st derivative gives velocity;
d r(t)/ dt = 2t i + 6 j + 4/t k
2nd derivative gives acceleration;
d^2 r(t)/ dt^2 = 2 i - 4/ t^2
Speed ;
Square root of (4 t^2 + 36 + 16/ t^2)
For a given time, like 2 seconds, t will be 2. And answer of speed will be scalar.