A rock is dropped from the top of a 45-meter tower, and at the same time a ball is thrown from the top of thetower in a horizontal direction. Air resistance is negligible. The ball and the rock hit the level ground adistance of 30 meters apart. The horizontal velocity of the ball thrown was most nearly
(A) 5 m/s
(B) 10 m/s
(C) 14.1 m/s
(D) 20 m/s
(E) 28.3 m/s

A3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular? a 3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular?

Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 11 cm in diameter, separated by 1.0 cm. how much charge can be added to each of the plates before a spark jumps between the two plates? for such flat electrodes, assume that value of 3×106n/c of the field causes a spark.

How are positive ions different from neutral atoms