Conceptual Physics

Variables

Part 1: Constant velocity

Part 2: Constant acceleration

What is the strategy?

1. Use the definition of velocity to find the velocity of the mouse car before it accelerates. The velocity is constant during the first part of the
   journey.


2. Use the definition of acceleration and solve for the final velocity.

Physics principles and equations

The definitions of velocity and acceleration will prove useful. The velocity and acceleration are constant in this problem. In this and later
problems, we use the definitions for average velocity and acceleration without the bars over the variables.

v = ǻx/ǻt

a = ǻv/ǻt = (vfívi)/ǻt

Step-by-step solution

We start by finding the velocity before the engine fires.

Next we find the final velocity using the definition of acceleration. The initial velocity is the same as the velocity we just calculated.

displacement ǻx = 10.3 m

elapsed time ǻt = 4.15 s

velocity v

initial velocity vi = v (calculated above)

acceleration a = 1.22 m/s^2

elapsed time ǻt = 5.34 s

final velocity vf

Step Reason

1. v = ǻx/ǻt definition of velocity

2. v = (10.3 m)/(4.15 s) enter values

3. v = 2.48 m/s divide

Step Reason

4. a = (vf – vi)/ǻt definition of acceleration

5. enter given values, and velocity from step 3

6. 6.51 m/s = vf – 2.48 m/s multiply by 5.34 s

7. vf = 8.99 m/s solve for vf

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