Download Net force on the rickshaw?

Every action has
an equal and
opposite reaction.
Action and Reaction Pairs
Feet impact board
Board impacts feet
Fist hits neck
Neck hits fist
Bedouin pulls sheep
Sheep pulls bedouin
Wheels push road
Road pushes wheels
Action and Reaction on Different
Masses
Consider the recoil of a rifle…
Rifle :
Same Force
F
m
a
Bullet :
F
m

a
Same force
JACOBS :
F
m
 a Safety :
F
m

a
Action and Reaction on Different
Masses
Consider the launch of a space shuttle…
The shuttle continually recoils
against the expelled gas from
the rockets. No atmosphere is
needed for this interaction.
Do Action and Reaction Forces Cancel?
It depends on context…
If the car and the man are
the system, then the force
pair is internal. This action
reaction does cancel out.
BUT…
If the car is the system,
then the man is an external
force acting against it. This
action reaction does not
cancel out. The external
force of the road against
the man accelerates the
system.
Force and Friction
The Rickshaw Problem
Pull of man on rickshaw
Pull of rickshaw on man
Friction b/w cart wheels and ground
Push of ground on man
Push of man on ground
Acceleration is due to net force
The Rickshaw Problem
Net force on the rickshaw?
Pull of man – friction of wheels on ground
Net force on the man?
Push of ground on man - Pull of rickshaw on man
Net force on the ground?
Push of man on ground – friction of ground on wheels