An object swings in a horizontal circle, supported by a 1.8-m string. It swings at a speed of 3 m/s. What is the mass of the object given that the tension in the string is 90 N?

Mass = 18 kg

Explanation:

Formula for force in centripetal motion is;

F = mv²/r

We have;

Mass; m.

Speed; v = 3 m/s

radius; r = 1.8 m

Force; F = 90 N

Thus;

Making m the subject;

m = Fr/v²

m = 90 × 1.8/3²

m = 18 kg

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:

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)