Motion at constant acceleration

In summary, a car with a deceleration of 7m/s^2 left skid marks 92m long on the highway. Using the equation vf^2-vi^2=2ad, the estimated speed of the car just before braking is 35.889 m/s. However, this solution is based on the assumption that distance divided by deceleration gives time and that the equation x=x0+v0t+1/2at^2, which is for displacement, can be used to find speed. It is important to note that there may not have been enough information provided to accurately solve the problem.
  • #1
steve snash
50
0

Homework Statement


In coming to a stop, a car leaves skid marks 92m long on the highway. Assuming a deceleration of 7.00m/s^2 estimate the speed of the car just before braking.


Homework Equations



deceleration=7m/s^2, distance=92m

The Attempt at a Solution


I found there was not enough information to solve the problem, but i had a go, assuming dividing the distance by deceleration you would get time. 92/7 =13.14 seconds

I substituted this into the equation of motion x=x0+v0t+1/2at^2
=52.99m/s. Is this right??

NEED TO KNOW BY TOMORROW
 
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  • #2
Why would distance divided by deceleration give you time? Why would x=x0+v0t+1/2at^2, which is an equation for displacement, give you speed?

Are you familiar with the equation vf^2-vi^2=2ad?
 
  • #3
so the answer should be vi^2=2(7)(92)
=square root 1288=35.889 m/s??
 

Related to Motion at constant acceleration

What is constant acceleration?

Constant acceleration is when an object's velocity changes at a constant rate. This means the object's speed increases or decreases by the same amount over equal intervals of time.

What is the equation for motion at constant acceleration?

The equation for motion at constant acceleration is v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time elapsed.

How does acceleration affect an object's motion?

Acceleration affects an object's motion by changing its velocity. A positive acceleration will cause the object to speed up, while a negative acceleration (or deceleration) will cause the object to slow down.

What is the difference between constant acceleration and uniform acceleration?

The terms constant acceleration and uniform acceleration are often used interchangeably, but technically they have slightly different meanings. Constant acceleration refers to a situation where the acceleration remains the same throughout the entire motion, while uniform acceleration refers to a situation where the acceleration remains the same in both magnitude and direction.

How is motion at constant acceleration represented graphically?

Motion at constant acceleration is represented graphically by a straight line on a velocity-time graph. The slope of the line represents the acceleration of the object, and the area under the line represents the displacement of the object.

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