WEBVTT

1
00:00:00.000 --> 00:00:11.749
Here is the problem: An object starts at 20 m/s and accelerates at 1.5 m/s squared for 10 s. How far does it go and how fast is it moving?

2
00:00:12.199 --> 00:00:18.910
Find displacement s and final velocity v for motion in a straight line with constant acceleration.

3
00:00:19.710 --> 00:00:25.352
List the known quantities. Unknown: displacement s and final velocity v.

4
00:00:25.802 --> 00:00:26.975
Final velocity.

5
00:00:27.425 --> 00:00:28.365
Displacement.

6
00:00:29.165 --> 00:00:36.700
So the answer is s equals 275 m, v equals 35 m/s.

7
00:00:37.150 --> 00:00:50.200
With constant acceleration, any three of displacement, initial velocity, final velocity, acceleration and time fix the other two. Each pair of unknowns is solved with the equation that does not contain the other unknown.

8
00:00:51.000 --> 00:00:59.661
Check v squared equals u squared plus 2as: 1225 equals 1225.