một quả cầu kim loại bán kính 50cm đặt trong chân không tích điện Q = 5*10^-6, tính điện thế tại tâm của quả câu

Ineed the answer to question 1 , i’m desperate

Agroup of students were investigating the force of gravity. they began by dropping a foam ball from a height of 3 meters into a bucket of sand. the ball hit the sand in 0.306 seconds. they dropped additional balls of approximately the same diameter, but of different masses. here is the data they collected. based on this experiment and the collected data, what would their conclusion be?

You throw a baseball directly upward at time =0 at an initial speed of 14.9 m/s. what is the maximum height the ball reaches above where it leaves your hand? ignore air resistance and take =9.80 m/s2.