Một quả cầu kim loại có khối lượng 0,2 g được treo trên một sợi dây cách điện được đặt trong một điện trường E có phương thẳng đứng, chiều từ dưới lên như hình vẽ. Cho biết gia tốc trọng trường g = 10 m/s^2. Nếu lực căng dây là 0,004 N, thì điện tích của quả cầu là:

A30 kg weight lies on top of a massless piston of area a = 0.01 m2 the exterior air is at a (constant) p =1 atm and t = 27 c. the interior gas is 0.4 moles of (ideal) n2 and it has initial temperature 27.00 degrees c. 1. what is the initial pressure in the interior? a. 29.4 kpa b. 130.7 kpa c. 101.3 kpa the next three questions concern what happens when an amount of heat q is slowly added to the interior, raising the piston by 1 mm and raising the interior temperature to 27.40 c

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.

Why does a collision with an airbag cause less damage than a collision with a steering wheel