Question

A 115 kg person is running at a constant speed of 3.10 m/s when they try to stop on a level surface. If the coefficient of friction is 0.645, what is the force of friction that acts on the person?

A 1.5 C charge has an electron dropped 3.0 m away from it. Determine the electric field strength at this point. Create a diagram of the electric field lines around the charge and predict the direction that an electron would travel

Answer 1

m = mass of the person = 115 kg

= coefficient of friction = 0.645

Force of friction is given as

f = mg

f = (0.645)(115)(9.8)

f = 726.92 N

Q = magnitude of the charge = 1.5 C

r = distance of location of electron from the charge = 3 m

Electric field strength at the location of electron is given as

E = k Q/r²

E = (9 x 10⁹)(1.5)/(3)²

E = 1.5 x 10⁹ N/C

hence the electron moves towards the charge.