Calculating Deceleration: Swati's Story

In summary, the formula for acceleration is a = Δv/Δt and to calculate the deceleration in this scenario, we can use the equation a = (v2 - v1)/Δt where v1 = 39 m/s and v2 = 27 m/s. This gives a deceleration of 2 m/s².
  • #1
ImsoFly
48
0

Homework Statement


Swati was driving her car over the speed limit when an oncoming car car flashes its lights warning her of a radar trap ahead. She decelerates from 39 m/s to 27 m/s in 6.0 s. What deceleration did her brakes apply?

- I am not sure what formula to use so does anyone have a clue what formula i could use for this question? Thanks for taking your time.:smile:
 
Physics news on Phys.org
  • #2
Well, what's the definition of acceleration (or in this case deceleration) that you have come across in your lessons, or in your textbook?
 
  • #3
umm well my teacher taught us this new displacement formula but i dunt think its related to the question i need help with .. but this is the formula he taught us: d= v1 deltat+1/2 a(deltat)2 sorry i dunt kno how to make the traingle for delta and the arrow heads... I am new to this
 
  • #4
but we usually use the average velocity=delta d/delta t formula..
oh..i fthink its this formula a=delta t + v2-v1 is this correct?
 
Last edited:
  • #5
[tex]\[
a = {\textstyle{{\Delta v} \over {\Delta t}}}
\][/tex]
 
  • #6
thanks KingNothing
 
  • #7
But if i was to use a=delta v/delta t .. how do i put to veclotiys? 39 m/s to 27 m/s
 
  • #8
[itex]\Delta v[/itex] means "change in velocity" just like [itex]\Delta t[/itex] means change in time. Here, the change in time is 6 seconds, and the change in velocity is exactly what it sounds like it should be; namely (39-27)m/s.
 
  • #9
oh so would i just do 39-27? which is 12 m/s?
 
  • #10
Yup, then substitute into the equation for acceleration.
 
  • #11
Alright, thanks a lot cristo for ur help and KingNothing for the formula. Thanks.
 

1. How do you calculate deceleration?

To calculate deceleration, you need to know an object's initial velocity, final velocity, and the time it takes to change from the initial velocity to the final velocity. The formula for deceleration is (final velocity - initial velocity) / time.

2. What is the unit for deceleration?

The unit for deceleration is meters per second squared (m/s²).

3. Is deceleration the same as negative acceleration?

Yes, deceleration is the same as negative acceleration. Both terms refer to a decrease in an object's speed.

4. Can deceleration be greater than acceleration?

No, deceleration cannot be greater than acceleration. Acceleration is a measure of how much an object's speed increases, while deceleration is a measure of how much an object's speed decreases. The magnitude of acceleration is always greater than the magnitude of deceleration.

5. How does deceleration affect an object's motion?

Deceleration causes an object to slow down or decrease in speed. This means that the object is moving with a negative acceleration, or in the opposite direction of its initial velocity.

Similar threads

  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
4K
  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Back
Top