It takes 487.5J to heat 25 grams of copper from25 °C to 75 °C. What is the specific heat in Joules/•g°C?
A. 0.39 J/g°C
B. 0.78 J/g°C
C. 609000 J/g°C
D. 589 J/g°C

Two 2.0-cm-diameter disks face each other, 1.0 mm apart. they are charged to ±10 nc. what is the electric field strength between the disks? a proton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?