A 20 kg ladder 10 m long is leaned against a frictionless wall at an angle of 55°. A 60 kg electrician slowly climbs the ladder. The coefficient of static friction between the ladder and the floor is 0.5. How far up the ladder can she climb before it starts to slip? If she resets the ladder at a higher angle, she can go all the way to the top. What is the minimum angle?

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.

A100-watt light bulb illuminates a solar cell. the electricity from the solar cell operates a water pump that delivers 1 watt of power. what is the efficiency of the system?

Which form of cell division creates the sperm and egg, resulting in half of the chromosomes as the other cells?