Find time given velocity and distance

In summary, the given equations for velocity and displacement are needed to solve for the magnitude of acceleration required for a vehicle to stop in 29 m at a speed of 28 m/s. The answer is 13.52 m/s^2. Additionally, using the same equations, we can determine that it takes the vehicle approximately 2 seconds to travel 27 m, giving the jaywalker that much time to move out of the way.
  • #1
Calhoun295
3
0

Homework Statement



A certain vehicle requires a distance of 29 m to stop when it is traveling at 28 m/s.
(a) What magnitude of acceleration is produced by braking under these conditions?
(b) If a jaywalker is 27 m in front of the vehicle when the driver first applies the brakes, how much time does the pedestrian have to get out of the way?

Homework Equations



v=vo + at
x - xo = vot + [tex]\frac{1}{2}[/tex]at2
v2 = vo2 + 2a(x - xo)

are the given equations for what we're learning.

The Attempt at a Solution



(a) 13.52m/s2
(b) is what I cannot find
 
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  • #2
I'll rephrase the question: How long does it take the vehicle to cover 27 m?
 

1. How do you calculate time given velocity and distance?

To calculate time given velocity and distance, you can use the formula time = distance/velocity. This means that you divide the distance traveled by the speed or velocity at which the object is traveling. The resulting value will give you the time it takes for the object to cover that distance at that velocity.

2. What units should I use for velocity and distance when calculating time?

When calculating time using the formula time = distance/velocity, it is important to use the same units for both distance and velocity. For example, if the distance is given in kilometers and velocity is given in kilometers per hour, the resulting time will be in hours. It is also important to use consistent units throughout all calculations to avoid errors.

3. Can time be negative when calculating time given velocity and distance?

No, time cannot be negative when calculating time given velocity and distance. Time is a measure of the duration of an event, and it cannot have a negative value. If the resulting time is negative, it means that there was an error in the calculation or the given values were incorrect.

4. What other factors can affect the time calculated using velocity and distance?

Aside from velocity and distance, other factors that can affect the time calculated include external forces like friction and air resistance, as well as the shape and weight of the object. These factors can impact the overall speed or velocity of the object, therefore affecting the time it takes to cover a certain distance.

5. Can the formula for calculating time given velocity and distance be applied to all types of motion?

Yes, the formula time = distance/velocity can be applied to all types of motion, as long as the velocity and distance are constant. This means that the object is moving at a constant speed and covering a fixed distance. For cases where the velocity or distance is changing, more complex formulas may need to be used.

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