Speed, velocity & acceleration

[lexi]

1. Homework Statement ---------->
At a time = 0, a car has a constant velocity of 20 m/s east. At the same time a motorcycle starts from rest in the same direction with an accelerationof 2 m/s2. How long does it take the motorcycle to catch up with the car, and what distance have they traveled by that time?

2. Homework Equations



3. The Attempt at a Solution

Do you use the equation: x-x0 = v0t + 1/2at^2?

Please help! I really want to learn this so if you could show me the steps that would be great! How do you know what equation to use??

Thanks!

 

[Doc Al]

At a time = 0, a car has a constant velocity of 20 m/s east. At the same time a motorcycle starts from rest in the same direction with an accelerationof 2 m/s2. How long does it take the motorcycle to catch up with the car, and what distance have they traveled by that time?

I presume the car has a head start! If the motorcycle is at x=0 at t=0, where is the car at that time?

Write expressions for the position of each as a function of time. Then solve for the time when their positions are equal.

 

[Doc Al]

I presume the car has a head start! If the motorcycle is at x=0 at t=0, where is the car at that time?

Of course, the car doesn't have to have a head start. (My bad.) I guess that's what you meant. In which case, at t=0 both are at x=0.

 

[einstein_a_go_go]

Sketch the graphs of motion and then look at areas under graphs...no need for equations as such.