Ll of mass m is thrown vertically upward with an initial speed of v0. it experiences a force of air resistance given by f = -kv, where k is a positive constant. the positive direction for all vector quantities is upward. the differential equation for determining the instantaneous speed v of the ball in terms of time t as the ball moves upward is

the diferencial equation is

dv(t)/dt + (k/m) v(t) + g = 0

Explanation:

the differential equation for determining the instantaneous speed can be found from Newton's second law:

F= m*a

F drag + F gravity = m*a

(-k*v) + (-m*g) = m*a ,  where g is acceleration due to gravitational force

since a = dv/dt and dividing both sides by m

dv(t)/dt = -g- k/m v(t)

or

dv(t)/dt + (k/m) v(t) + g = 0

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.

wire in brush may conduct electricity from cell to drill and vice versa electrc shock possible