The physics of engine breaking.
Engine braking is the slowing of a motorcycle by changing the ratio of rpm of the motor to the rpm of the wheels on the ground. This can be accomplished by down shifting the transmission of the engine and then letting out the clutch. Because of the differences in rates of rpm the tires will spin the motor rpm to match the necessary rpm to turn the tires at the desired rate. This in turn takes the transnational kinetic energy of the vehicle and transfers it into rotational kinetic energy of the motor. Because energy must be conserved in a system the transfer from transnational energy to rotational energy causes a decrease in speed of the motorcycle.
Engine braking is the slowing of a motorcycle by changing the ratio of rpm of the motor to the rpm of the wheels on the ground. This can be accomplished by down shifting the transmission of the engine and then letting out the clutch. Because of the differences in rates of rpm the tires will spin the motor rpm to match the necessary rpm to turn the tires at the desired rate. This in turn takes the transnational kinetic energy of the vehicle and transfers it into rotational kinetic energy of the motor. Because energy must be conserved in a system the transfer from transnational energy to rotational energy causes a decrease in speed of the motorcycle.
Photo credit “Total Internal Reflection.” Total Internal Reflection, hyperphysics.phy-astr.gsu.edu/hbase/rke.html.
When engine braking happens the 1/2 as well as the moment of inertia and the mass stay the same. Therefore the only two other variables in the equations that affect the energy outputs are the linear velocity and angular velocity. In this system energy is conserved, so if the engine rpm increases the linear velocity must decrease.