The motor does 20 J of work on the block, it means that the total mechanical energy of the block has increased by 20 J. But the increase in total mechanical energy is equal to the sum of the increases in potential energy and kinetic energy:

So, if the gravitational potential energy has increased by 15 J, the kinetic energy has increased by
As you approach the surface of the sphere very closely, the electric field should resemble more and more the electric field from an infinite plane of charge.
If you check Gauss's law (recalling that the field in the conductor is zero) you will see that if the surface charge density is σ=Q/4πR2, then indeed the field at the surface is σ/ϵ0 as in the infinite charge of plane case.
Such a field is constant, the field lines are parallel and non-diverging, and the infinities associated with the field due to point charge do not arise.
Explanation:
Produce power through the circuit.
Answer:
The total amount of CO₂ produced will be = 20680 kg/year
The reduction in the amount of CO₂ emissions by that household per year = 3102 kg/year
Explanation:
Given:
Power used by household = 14000 kWh
Fuel oil used = 3400 L
CO₂ produced of fuel oil = 3.2 kg/L
CO₂ produced of electricity = 0.70 kg/kWh
Now, the total amount of CO₂ produced will be = (14000 kWh × 0.70 kg/kWh) + (3400 L × 3.2 kg/L)
⇒ The total amount of CO₂ produced will be = 9800 + 10880 = 20680 kg/year
Now,
if the usage of electricity and fuel oil is reduced by 15%, the reduction in the amount of the CO₂ emission will be = 0.15 × 20680 kg/year = 3102 kg/year