This is a velocity versus time graph of a car starting from rest. if the area under the line is 10 meters, what is the corresponding time interval?

a. 2 seconds
b. 4 seconds
c. 5 seconds
d. 10 seconds
e. 15 seconds

So the area under a velocity time graph is distance or displacement, if you have done calculus yet you will understand that if you take the integral of a velocity function then you end up with displacement. Thats for later understanding however.

So this appears to be a right triangle so we can find the area of a triangle as:

0.5bh = A

Since our area is 10 meters lets alter our formula a bit to fit the situation:

Our base here is time and our height is velocity so:

0.5tv = Δx

So we can read off the graph that our velocity at the end, or our final velocity appears to be near 2.0 m/s

So we have v, and Δx so lets isolate for time by dividing by v and 0.5

t = Δx / 0.5v

Now lets plug all that in:

t = 10 / 0.5(2)

t = 10 seconds

Hope this helped!

c.the charges if the proton and electron and gravity

a lot of it means it can be "burned" for energy and sold at one price. if it is scarce, the price will go up