The phrase "at certain speeds" is correct and usable in written English.
It can be used when discussing the behavior or characteristics of an object or phenomenon that varies depending on the speed at which it is moving.
Example: "The vehicle's fuel efficiency improves at certain speeds, making it more economical for long-distance travel."
Alternatives: "at specific velocities" or "at particular rates".
An internal-combustion engine, by contrast, produces maximum torque only at certain speeds.
For any rotating machine, as the speed of rotation is increased, it may be observed that at certain speeds the shaft of the machine will oscillate or vibrate.
If you could automate traffic flows – that is, mandate certain cars to go in certain directions and at certain speeds – you would have the makings of an automotive social network.
As excitation frequencies of engines and propellers fluctuate with changing rpm and natural frequencies of ship and some local structures change with loading conditions, resonance at certain speeds often appears unavoidable.
And why bother with an override switch if the car's computer still tells the deflector to move up or down at certain speeds?
At least for now, the theory of energy minimization is coming out on top, suggesting that the gaits that feel the most "natural" to us are the ones that require the least amount of energy at certain speeds.
With the above observation from Figs. 1, 2, 3, and 4, it is clear that, the output torque of an IC engine may achieve the maximum value at certain speed range that is near the speed of the least fuel consumption.
Our studies show us over time that at a certain speed, it's virtually impossible to play at a certain position in the National Football League and play well".
When spun at a certain speed, the miniature sculptural forms, each staggered at a different stage of movement, analog-animate into an integrated (and horrific) whole.
In this setting, when it is no longer possible to derive the typical patterns of a particular driver's distinct style of turning corners or cruising at a certain speed, what parameters will be applied to arrive at a fair calculation of risk?
At a certain speed, all things disintegrate.
