Question

Leaving home in the morning, I back down my driveway. Before entering the road, I realize I forgot my lunch and so I pull back in to my parking spot.

What is my velocity just before I realized I forgot my lunch and stopped?

What is my velocity the instant after I realized I forgot my lunch and started moving back

towards my parking spot?

A change in velocity is an acceleration. Did I accelerate, from the moment just before I

stopped the car to the moment just after I started moving back towards my parking spot?

Answer 1

Answer:

Let us go to the basics first.

To answer this question, we shall assume some variables:

Assumption 1.Let us assume that the velocity with which you started to drive = V m/s

So, your velocity just before you realized that you forgot your lunch and stopped = +V m/s (Answer)

So, when you remembered you have forgotten your lunch, you stopped and started to move back towards your parking lot.

Assumption 2.I assume that you maintained same speed with which you started your journey.

Assumption 3.I also assume that this journey was unidirectional i.e., in one-dimesion straight line. But when you moved back your direction will change.

So, your velocity the instant after you realized that you forgot your lunch and started moving back towards your parking spot = -Vm/s   (Answer)

Yes, you accelerated as you changed your velocity from +V m/s to -V m/s.   (Answer)

So, acceleartion in this case can be calculated as :

Acceleartion, a = [(Final velocity) – (Initial velocity)]/Time taken

=>a = [(-V) – (V)]/T                (Let you took time = T)

=>a = -2V/T                           (ANSWER)

Thanks!!!