Frequently, attention in an equilibrium situation is confined to a plane. an example would be a ladder leaning against a wall, which is in danger of slipping only in the plane perpendicular to the ground and wall. by orienting a cartesian coordinate system so that the x and y axes are in this plane, choose which of the following sets of quantities must be zero to maintain static equilibrium in this plane. ∑fx and ∑τz and ∑fy
∑fz and ∑τx and ∑τy
∑τx and ∑fx and ∑τy and ∑fy
∑τx and ∑fx and ∑τy and ∑fy and ∑τz

Askydiver weighing 140 lb (including equipment) falls vertically downward from an altitude of 19,000 ft and opens the parachute after 18 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.55|v| when the parachute is closed and is of magnitude 14|v| when the parachute is open, where the velocity v is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. (a) find the speed of the skydiver when the parachute opens. (b) find the distance fallen before the parachute opens. (c) what is the limiting velocity vl after the parachute opens? (d) determine how long the sky diver is in the air after the parachute opens. (e) plot the graph of velocity versus time from the beginning of the fall until the skydiver reaches the ground.

Choose a synonym for the underlined homonym (a word with two or more meanings). i did not expect the boat to rock so much. a. boulder c. astound b. sway d. shock

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up