Question 3 Maria makes an electromagnet shown in the figure below. The battery has a voltage of 6.0V, and she uses an iron nail. Which of the following would increase the strength of the magnetic field produced?
Direction of
Current
North
Pole
South
Pole
A
Doubling the number of times the wire wraps around the nail
B
Changing the battery to a 3.0V battery
Reversing the direction of the current flow.
D
Replacing the iron nail with one made of plastic

Adding more pulleys to a system of pulleys needed to lift an object. a. increases the force b. decreases the force c. increases the amount of work d. decreases the amount of work

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.

Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?