Kinematics in One Dimension Problem

[pstfleur]

1. In getting ready to slamdunk the ball, a basketball player starts from rest and sprints to a speed of 6.0m/s in 1.5seconds. Assuming that the player accelerates uniformly, determine the distance he runs



2. Vf=Vo+at, VF^2=Vo^2+2a(Delta x)



3. Vf= 0m/s+(6.0)(1.5)= 9
Delta X= Vf^2-V0^2/2a= 81-0/12=6.75

Delta X should be the distance he's running. The book answer is giving me 4.5m, but I am coming up with 6.75..Am I plugging in wrong values?

 

[rock.freak667]

3. Vf= 0m/s+(6.0)(1.5)= 9

6.0 m/s is a velocity not an acceleration. In other words, you need to find the acceleration,a. Vf=6 not a.

 

[pstfleur]

6.0 m/s is a velocity not an acceleration. In other words, you need to find the acceleration,a. Vf=6 not a.

Thanks.. That was the key.. Is there an easier way to understand which is velocity and which is acceleration. I am always having a hard time figuring out which is which.

 

[chislam]

... a basketball player starts from rest and sprints to a speed of 6.0m/s ...

Both, speed and the units m/s are keywords for velocity.

Before you start plugging away on formulae and doing math, wrap your head around the concepts of physics first. If you can't do that, you're bound for disaster.