It's very tough to use the drop-down menus for this. I'll just do the best I can without them.
-- Objects with the same charge repel each other with electrostatic force, and attract each other with gravity. You can ignore the gravity because the electrostatic force is so much stronger.
-- Objects with opposite charge attract each other with electrostatic force, and also attract each other with gravity. You can ignore the gravity because the electrostatic force is so much stronger.
-- Objects with no charge have no electrostatic force between them, and they only attract each other with gravity.
A: 0.7 -0.8 and 0hrs
B: 0.2 - 0.4 and 1.0 -1.1 hrs
C: 0-0.2 hrs and 0.8 - 1.0 hrs
D: 0.4 - 0.7 hrs
Answer:
640 J
Explanation:
ΔKE = KE − KE₀
ΔKE = ½ mv² − ½ mv₀²
ΔKE = ½ m (v² − v₀²)
ΔKE = ½ (80 kg) ((5 m/s)² − (3 m/s)²)
ΔKE = 640 J
Her kinetic energy increases by 640 J, so she does 640 J of work.
