5 2. A truck took 4 hours to complete a journey. At the first 2h,
it travelled at an average speed of 70 km/h. For the rest of
the journey, it travelled at an average speed of 80 km/h.
What was the total distance of the journey?

300km

Explanation:

we use the formula s=d/t and solve for d.

d=st

s1=70km/h

s2=80km/h

t=2h

total d= (ts1)+(ts2)

=2(70)+2(80)

=300km

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: