18 votes

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

the amount of energy used per engine revolution is fixed (not precisely true I know) This is the error. The work per engine revolution is the torque at the engine. If the energy dissipation per wheel ...
Dale's user avatar
  • 100k
10 votes

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

Ignoring all losses from the gearbox on to the wheels, let’s just look at the engine. Internal combustion engines are about 30% efficient. About 65% of the energy is lost as heat, 5% as friction. ...
Rich's user avatar
  • 829
10 votes

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

If you are in a situation where the energy used to keep the car moving is unchanged, but you are putting more energy into the engine, then the difference must be losses in the engine. Whether you are ...
Cort Ammon's user avatar
  • 48.9k
10 votes
Accepted

Why can an applied force exceed static friction *without slipping* when both objects are free?

To quickly review, friction arises because when two objects are being driven to slide past each other, any sliding generally incurs an energy penalty (because of dissipative interactions at the ...
Chemomechanics's user avatar
9 votes
Accepted

How does rolling without slipping happen physically?

"What is the mechanism that assures the equality v=Rω, and under what conditions does it work?" The condition when the friction force at the interface between the wheel's edge and the ...
DKNguyen's user avatar
  • 9,309
8 votes

Why can an applied force exceed static friction *without slipping* when both objects are free?

The forces of static friction only need to accelerate $m_2$, the lower block. $F_{max}$ is the force to accelerate both blocks at the same rate. Thus it can be higher than the static friction -- its ...
Cort Ammon's user avatar
  • 48.9k
6 votes

How does rolling without slipping happen physically?

When an aircraft comes into land it wheels are essentially moving horizontally but have no rotation. When the wheels make contact with the runway there is obviously a torque acting to rapidly spin the ...
KDP's user avatar
  • 3,395
5 votes

Energy loss due to friction in Rolling Motion

Rather, the answers everywhere seem to indicate that NO energy is lost due to friction when rolling without slipping. Energy can be lost in the form of rolling resistance, sometimes called rolling ...
Bob D's user avatar
  • 71.8k
3 votes

Energy loss due to friction in Rolling Motion

Consider the energy of a rolling body, $$KE(t) = KE(t_0) - Energy\ lost\ to\ friction$$ If the energy lost to friction is zero, the kinetic energy is constant. In a freely rolling body the rotational ...
Rich's user avatar
  • 829
2 votes

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

No matter what causes them, energy "losses" inside an engine go directly to heat. This makes the engine warmer, making to coolant warmer trying to not overheat the engine.
StanS's user avatar
  • 41
2 votes

Where does "excess" energy go when a vehicle uses a lower gear to move at a given speed?

At the same vehicle speed, a lower gear requires more revolutions but less force — you don't need to depress the gas pedal all the way in the lower gear but may have to in a higher gear. But in the ...
Peter - Reinstate Monica's user avatar
1 vote
Accepted

Jump conditions and energy flux between moving block and floor

The flux of mechanical energy, $\pmb{n}\cdot \pmb{\tau}\cdot \pmb{u}$, is still valid at any surface where all of the variables are well defined. So as you approach the discontinuity from one side you ...
Dale's user avatar
  • 100k
1 vote

How does rolling without slipping happen physically?

Imagine a rolling wheel. Rolling without slipping can occurs when the velocity $v$ is constant and the wheel of radius $r$ has exactly the correct angular velocity $\omega=v/r$. The mechanism is that ...
my2cts's user avatar
  • 24.2k
1 vote

How to calculate fuel consumption of car (mpg) from speed and acceleration, knowing mass, drag coeff and rolling resistance?

there is an online calculator which gives answer to your question: https://www.gribble.org/cycling/power_v_speed.html It presents the result for the given parameters. The only thing you need to do is ...
Piotr's user avatar
  • 9

Only top scored, non community-wiki answers of a minimum length are eligible