Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Jacques. Which of the following are true statements? 

The Moon does not crash into the Earth because

An athlete holds a 7.5-kg shot put in his hand with his lower arm horizontal, as shown in the figure. His lower arm has a mass of 2.8 kg and its center of gravity (or center of mass) is 12 cm from the elbow-joint pivot. How much force must the extensor muscle (which is  M in the figure) in the upper arm exert on the lower arm? 

The curved section of a horizontal highway is a circular unbanked arc of radius 740 m.  If the coefficient of static friction between this roadway and typical tires is 0.40, what would be the maximum safe driving speed for this horizontal curved section of highway?

As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest? 

Salt water is denser than fresh water.  A ship floats in both fresh water and salt water.  Compared to the fresh water, the volume of water displaced in the salt water is

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle with a radius of 600 m. At the bottom of the dive, the speed of the airplane is 150 m/s. What is the apparent weight of the 70-kg pilot at that point?

As shown in the figure, fluid fills a container having several sections. At which of the indicated points is the pressure greatest? 

Identify the following face and leg markings.                                                                                     

Tumor suppressor genes act like brakes in the cell cycle.