A kayaker needs to paddle north across a 100 -m wideharbor. The tide is going out, creating a tidal current that flowsto the east at 2.0 m/s. The Kayaker can paddle with a speed of3.0m/s.
a. In which direction shoule he paddle in order to travel straightacross the harbor ?
b. How long will it take him to cross ?

a) 48.2 degrees north of west

b) 44.72 s

Explanation:

In order to travel straight across the harbor, his horizontal component velocity must be the same magnitude and opposite direction as the tidal velocity. So it should be 2m/s west ward

a. The direction would be:

cos α = 2/3

north of west

b. His vertical component of velocity would be

So the time it takes for him to cross the 100m river at the rate of 2.24 m/s is

100 / 2.24 = 44.72 s

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

iron would move it is magnetic there is a mag field around the current in the wire