Police Car Overtaking Speeder: How to Calculate the Time and Distance?

  • Thread starter Thread starter Monocerotis
  • Start date Start date
Click For Summary
SUMMARY

The discussion focuses on calculating the time and distance for a police car to overtake a speeder. The police car travels at a constant speed of 90 km/h and accelerates at 2.00 m/s² after being passed by a speeder traveling at 130 km/h. The problem requires applying the equations of motion for constant acceleration and constant velocity to determine when the positions of both vehicles are equal. The key equations used are x = x₀ + v₀t + (1/2)at² for the police car and x = x₀ + v₀t for the speeder.

PREREQUISITES
  • Understanding of kinematics, specifically equations of motion for constant acceleration and constant velocity.
  • Familiarity with unit conversions, particularly between kilometers per hour and meters per second.
  • Basic algebra skills to solve equations for time and distance.
  • Knowledge of initial conditions in motion problems, such as initial speeds and accelerations.
NEXT STEPS
  • Study the derivation and application of the equations of motion for constant acceleration.
  • Learn how to convert speeds from kilometers per hour to meters per second for accurate calculations.
  • Practice solving similar problems involving relative motion and acceleration.
  • Explore graphical methods for visualizing motion and solving kinematic problems.
USEFUL FOR

Students studying physics, particularly those focusing on kinematics, as well as educators looking for practical examples of motion problems involving acceleration and relative speed.

Monocerotis
Gold Member
Messages
54
Reaction score
0

Homework Statement



A police ar traveling a constant 90 km/h is passed by a speeder travelig 130 km/h. 1.00s after the speeder passes, the policeman steps on the accelerator. If the police car's acceleration is 2.00 m/s^2, how much time elapses after the police car is passed until it overtakes the speeder (assumed moving at a constant speed)



The Attempt at a Solution


This is my first encounter with these types of problems, at the level where I need to solve it without trial and error graphing.

Could someone provide a bit of guidance because I'm not sure how to do this problem.
 
Physics news on Phys.org
What is the position of the speeder at time t.
What is the position of the policeman at time t.
for what t are they equal.

motion with constant acceleration:
x = x_0 + v_0 t + (1/2) a t^2

motion with constant velocity
x = x_0 + v_0 t
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
1K
  • · Replies 11 ·
Replies
11
Views
4K
Replies
1
Views
1K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 25 ·
Replies
25
Views
4K
Replies
1
Views
2K
  • · Replies 11 ·
Replies
11
Views
7K
  • · Replies 8 ·
Replies
8
Views
7K