There are news reports of cars going out of control due to a sticking throttle.
Couldn't a clomp on the brakes bring it to a stop, even with the throttle open--or is this a Myth.
A job for Buster maybe?
Some calculations on the situation:
POWER REQUIRED
FOR
AUTOMOBILE
ACCELERATION AND BRAKING

ACCELERATION
Given: 4000 pound vehicle
Uniform acceleration 0 to 60 MPH (88 ft/sec) in 9 seconds
Acceleration = 88 ft/sec/9 sec = 9.8 ft/sec/sec
Gravity = 32 ft/sec/sec= 1 g
So acceleration of car= 9.8/32= 0.3 g

Force= mass x acceleration

Pounds= slugs x ft/sec/sec

4000 pounds/ 32 ft/sec/sec = 125 slugs

Force to accelerate car:
Pounds = 125 slugs x 9.8 ft/sec/sec = 1225 pounds

Work= change in kinetic energy
W = ½ x mass x velocity^2
W= ½ x 125 slugs x 88 ft/sec^2 = 484,000 ft-pounds

Since this work was done in 9 seconds,

Power = 484000/ 9 = 53,778 ft-lb/sec
Since 550 ft-lb/sec = 1 horsepower
Power = 53778/550 = 97.8 HP

BRAKING
Given: 4000 pound vehicle braked from 60 MPH (88 ft/sec) to 0 in 140 ft.

Work done in stopping vehicle=
W = ½ x 125 slugs x 88 ft/sec^2 = 484,000 ft-lb (same as for acceleration)



Average velocity = 44 ft/sec
Distance = average velocity x time
140 = 44 x time
Time = 140/44 = 3.18 sec

Power = 484000/3.18 = 152,200 ft-lb/sec

Power = 152000/550 ft-lb/sec/HP = 277 HP

Power from brakes is much more than from engine

BRAKING WITH THROTTLE OPEN


Net HP for braking = 277 – 98 = 179 HP

Then 179 HP x 550 ft-lb/sec/HP = 98,450 ft-lb/sec

So to provide the required stop from 60 MPH (88 ft /sec)
484,000 / time = 98450 ft-lb/sec
Time = 4.9 sec
So at average velocity while braking of 44 ft/sec

Vehicle would travel 44 ft/sec x 4.9 sec = 216 ft while stopping with full throttle---- quite long but still stopped.
Looks like a challenge for Mythbusters.

Only one problem with your calculations:

Cars don't go out of control because of a sticking throttle, it's because people are stupid, and don't think about steady breaking or in worst case, cutting power to the engine!

remember also, with the pious (not a typo) the brakes are failing, too.

not that thats a bad thing.

quote:

Originally posted by fifth horseman:
remember also, with the pious (not a typo) the brakes are failing, too.

not that thats a bad thing.

Under certain situations, the effects of the brakes would be delayed as it switched from the energy recovery system to normal braking, which takes less than a second.
Which is enough time for people to think about “no win no fee” lawyers and how much money they can make!

i just meant that less hybrid car drivers (and less hybrid cars) is good for everyone.

quote:

Originally posted by fifth horseman:
i just meant that less hybrid car drivers (and less hybrid cars) is good for everyone.

Do these cars not have ingition keys? On most cars, removal of the key stops the car. Even just turning it back a bit does the job. Knocking it out of gear helps as well. Then again, if anybody gets a car that can't be switched off and relies totally on software to keep them alive and doesn't have any way of de-powering itself, this is a good example of Darwinism in action.