# Thread: dependence speed to time, physics

1. ## dependence speed to time, physics

dependence speed to time, physics like in puctyre : http://www.x3m.biz/11a.png

2. ## Re: dependence speed to time, physics

I have no idea what "dependence of speed to time" means. It is not a complete sentence- there is no verb.

And I cannot read the language in your link. Since it says "a= v/t" and, further has a "7", "10 k/h", and "10/7". I might guess they are saying that the (average) acceleration in increasing speed by 10 k/h in 7 hours is 10/7 k per hour^2. You could also say that if you accelerate at 10/7 km per hour per hour for 7 hours, you speed will have increases by 10 km per hour (v= at).

3. ## Re: dependence speed to time, physics

According to Google translate the OP's picture says:

7s with a speed of 10 Km/hr
the ratio of speed to time
is 10/7.

I think the OP is misusing the formula for acceleration which is not v/t but rather change in velocity over time. If speed is constant at 10 Km/hr, then acceleration is 0. But if speed changes by 10 Km/hr in a period of 10 seconds then the acceleration is:

$a = \frac {\Delta v} t = \frac {10 \frac {Km}{Hr}}{7 s} = \frac {10 Km}{7 Hr-s} \times \frac {1000m}{1 Km} \times \frac {1 Hr}{3600 s} = 0.4 \frac m {s^2}$