Aboxer can hit a heavy bag with great force. why can't he hit a piece of tissue paper in midair with the same amount of force? a boxer can hit a heavy bag with great force. why can't he hit a piece of tissue paper in midair with the same amount of force? the boxer can only hit the tissue paper with a force as large as the tissue paper can exert on the boxer, and the low-mass tissue can only exert a weak force. the tissue paper can only exert a force on the boxer as large as the air resistance force exerts on the paper. the low-mass tissue exerts a smaller reaction force on the boxer than the action force the boxer exerts on the tissue. the low-mass tissue floating in the air exerts no reaction force on the boxer.

The boxer can just hit the tissue paper with a force as extensive as the tissue paper can apply on the boxer, and the low mass tissue can just apply a weak force.  

Let a boxer hitting on heavy bag. The boxer hits the bag while the bag hits back on the boxer and stops its movement. A pair of forces is engaged with the hitting the bag. The force pair can be quite large.  

Now considering boxer hitting a bit of tissue paper. The boxer can just apply as much force on the tissue paper as the tissue paper can apply on the boxer.  

The boxer can`t apply any force whatsoever except if what is being hit applies a similar amount of force back. An interaction requires a pair of forces acting on two separate objects.

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: