If an object starts at rest and moves 60 meters north along a straight line in 2 seconds, what is the average velocity?

The average velocity, expressed as a vector, is v=30 m/s with direction north.

Explanation:

In this case, we will obtain a vector velocity, and the correct answer will be expressed as a vector. But as the movement happens only along a straight line (with direction to the north from the point of rest), we can do the math calculation as a one-dimensional problem. Then the final velocity will be a vector with the calculated magnitude, pointing to the north, as we already know.

The question is simple, as we were given the distance in meters that the object moved in a straight line, and the time in seconds that took the object to move that distance, we have the correct units and we can write the average velocity as

where d is the distance, and t is the time. Therefore

which is the magnitude of the velocity we wanted to know, then we express it as vector saying its direction (north, for our system of reference).

true

explanation:

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: