Question

A 2.4 g plastic bead charged to -3.0 nC and a 4.2 g glass bead charged to 17.1 nC are 2.0 cm apart {center to center). a. What is the acceleration of the plastic bead? b. What is the acceleration of the glass bead? c. In what direction does each bead accelerate? (towards each other, away from each other, same direction, can't tell)

Answer 1

a)

m_p = mass of plastic bead = 2.4 x 10^-3 kg

q_p = charge of plastic bead = - 3 x 10^-9 C

m_g = mass of glass bead = 4.2 x 10^-3 kg

q_g = charge of glass bead = 17.1 x 10^-9 C

r = distance between beads = 0.02 m

F = force between the beads = k q_p q_g/r² = (9 x 10⁹) (3 x 10^-9) (17.1 x 10^-9)/(0.02)² = 0.00115 N

a_p = acceleration of plastic bead = F/m_p = 0.00115/0.0024 = 0.48 m/s²

b)

a_g = acceleration of glass bead = F/m_g = 0.00115/0.0042 = 0.27 m/s²

c)

towards each other . since they have opposite charge hence force is attaractive between them,