Homework Help: Physics - acceleration..need to find velocity

Posted by Belinda on Friday, October 21, 2011 at 11:22am.

I am given two points on an acceleration vs time graph: (-2,13),(4,0). When t = -2s, v = 10 m\s. What velocity at t = 6s? I believe acceleration average is (-13/6), but how do I solve the rest get the correct answer, which is 44.7 m/s? Any help or hints would be greatly appreciated.

Physics - acceleration..need to find velocity - Steve, Friday, October 21, 2011 at 1:14pm
If v=10 when t= -2, and you have negative acceleration, v is decreasing. How can it increase to 44.7? Is there a typo in here somewhere?
Physics - acceleration..need to find velocity - Steve, Friday, October 21, 2011 at 1:25pm
Never mind. I see acceleration is not constant.

However, I get 15.3 m/s. I will have to recheck my math.
Physics - acceleration..need to find velocity - Steve, Friday, October 21, 2011 at 6:48pm
OK. Finally got a moment,

If we assume a linear function for acceleration, and fitting it to the two points, we get

a = -13/6 t + 26/3

v = V₀ + 26/3 t - 13/12 t²

v(2) = 10 = V₀ - 26/3 * 2 - 13/12 * 4
10 = V₀ -65/3
V₀ = 95/3

So, now we know

v(t) = 95/3 + 26/3 t - 13/12 t²
v(6) = 95/3 + 26/3 * 6 - 13/12 * 36 = 44 2/3 = 44.7

Answer this Question

Related Questions

Physics - I am given two points on an acceleration vs time graph: (-2,13),(4,0...
physics - how do i make a velocity vs. time graph? i have a graph of ...
PHYSIC help! - a cart is pushed uphill on a ramp, goes up and momentarily stops...
Physics - i have a graph that shows the motion of a cyclist. as the velocity(m/s...
physics - Assume a canister in a straight tube moves with a constant ...
Physics - From the position vs time graph of an object moving with constant ...
physics - A football is thrown horizontally with an initial velocity of (16.5 m/...
physics - Consider the motion of an object along a straight path as shown in the...
Physics - An athlete starts at point A and runs at a constant speed of 5.40 m/s ...
Physics(check) - 13)What can you say about the motion of a body if its velocity-...

For Further Reading

First Name:
School Subject:
Answer: