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When a charged ball moves from point m to point n in the air, it is respectively affected by gravity, air resistance and electric field force. In the process of movement, the electric field force does 14J work on the ball, the ball overcomes the air resistance and does 4J work, and the kinetic energy of the ball increases 8j A. The gravitational potential energy of the ball at M is more than that at N 2 & nbsp; JB. The mechanical energy of the ball at M is more than that at n 4 & nbsp; JC. The mechanical energy of the ball at M is 10 & nbsp; more than that at n JD. The electric potential energy of the ball at M is 14 & nbsp; more than that at n J
A. According to the kinetic energy theorem: WG + W electricity + W resistance = △ EK, the gravitational work is WG = △ ek-w electricity - W resistance = 8j-14j - (- 4) J = - 2J, then the gravitational potential energy of the ball at m point is less than that at N point by 2J If w electricity + W resistance = 14J + (- 4) J = 10J, the mechanical energy of the ball at m point is 10J less than that at N point. So BC is wrong. If D and electric field force do 14J work on the ball, the electric potential energy of the ball at m point is 14J more than that at N point. So D is correct. So D is chosen
RELATED INFORMATIONS
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- 7. If the air resistance is directly proportional to the square of the object's velocity, and the air resistance is also directly proportional to the square of the object's cross-sectional area, can it be written as follows: If the air resistance is proportional to the square of the velocity of the object, the air resistance is also proportional to the square of the cross-sectional area of the object, Can it be written as: F = k.v & # 178;. S & # 178;
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- 19. I found this, ∵ 1pA * 1m & # 179; = 1n / m2 * 1m & # 179; = 1n · M = 1J work = pressure * volume
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