velocity

[soccerball3211]

(a) If a particle's position is given by x = (14) + (-15) t + (16) t2 (where t is in seconds and x is in meters), what is its velocity at t = 1 s? (b) What is its speed just then?

First I differentiate the displacement to get the velocity equation.

velocity=32t-15, then I plug in t=1 and get +17m/s

and then for part B i got 17 m/s?

Did I perform the right calculations?

 

[wjm11]

(a) If a particle's position is given by x = (14) + (-15) t + (16) t2 (where t is in seconds and x is in meters), what is its velocity at t = 1 s? (b) What is its speed just then?

First I differentiate the displacement to get the velocity equation.

velocity=32t-15, then I plug in t=1 and get +17m/s

and then for part B i got 17 m/s?

Did I perform the right calculations?

Your calculations are fine. What's being asked here is if you understand the difference between velocity and speed. Speed is a scalar (not a vector) meaning is has magnitude, but not direction. Velocity is a vector, meaning it has both magnitude and direction. If, for purposes of your problem, you've defined displacement to the right as being positive, then a positive velocity means the object is moving to the right; a negative velocity means it's moving to the left.

Hope that helps.