Question

5. Near the surface of Earth an electric field points radially downward and has a magnitude of about 100 N/C. Due to an electric charge, a penny (m=3.11 g) rises in the air with an acceleration of 0.150 m/s2 a. Draw the free body diagram of the penny. b. What is the weight of the penny? What is the net force on the penny? c. What charge (magnitude and sign) would have to be placed on the penny to achieve this acceleration?

Answer 1

Given, <a.s ă is net acceleration of penny. of m=3.11 gram a=0.150m/s2 met fe is electric force. Q ng is gravitational ng force. <b> Weight of penny is w=mg = 3.118 >W= 30.478x16” .: Met acceleration is a=0.15omis? .. from Neutton's and law, Net force on penny is Free = mea ni Farer= 3.11816*x0:15 N doreation - Fred= 0.4665410²N) is upward. <e.) Electric force Fe = 4 E where & is. magnitude of charge and € is magnitude of electric field. fer Electric field is downward 19. and electric force on charge es de upward so, charge should be negative. " Fe-ng=ma -. fe = mat mg=0.4665x40°+30.4786703 > 4*1000 = 30.9445x103 >1933.09x106c CS CamScann Sign of charge is negative