[30 point question]If you hold your arm outstretched with palm upward, the force to keep your arm from falling comes from your deltoid muscle. Assume that the arm has mass 4.0 kg and the distances and angles shown in (Figure 1). A. What force must the deltoid muscle provide to keep the arm in this position? (F=?)

B. By what factor does this force exceed the weight of the arm? (F/w=?)

Which atomic model was proposed as a result of j. j. thomson’s work?

Aball thrown by ginger is moving upward through the air. diagram a shows a box with a downward arrow. diagram b shows a box with an upward arrow. diagram c shows a box with a downward and upward arrow equal in size. diagram d shows a box with a downward and upward arrow with the downward arrow larger in size. which force diagram represents the forces on the ball? you may neglect the effects of air resistance.

35 grams of salt is dissolved in 500 grams of total solution. what is the percent by mass of salt?