Speed of Objects

  • #1
Physics Novice
1
0
As a stationary object, is it possible to determine the speed of an object as it approaches you? If so, how? ...and with accuracy?

For instance, if I'm standing on the sidewalk, can I determine the speed of a car on the road as it approaches me?
 

Answers and Replies

  • #2
Nugatory
Mentor
13,990
7,563
As a stationary object, is it possible to determine the speed of an object as it approaches you? If so, how? ...and with accuracy?

For instance, if I'm standing on the sidewalk, can I determine the speed of a car on the road as it approaches me?

Sure. Around here the traffic police use hand-held radar guns to catch speeders.
 
  • #3
CWatters
Science Advisor
Homework Helper
Gold Member
10,545
2,317
Time how long it takes the car to cover the distance between two objects (eg two lamp posts). Later measure the distance between the two lamp posts. Calculate the speed. The accuracy will be limited to how accurately you can measure the time. If the car casts a shadow on the lamp posts as it passes I'd suggest you can get quite an accurate measurement.
 
  • #4
DennisN
Gold Member
1,895
5,646
As a stationary object, is it possible to determine the speed of an object as it approaches you? If so, how? ...and with accuracy?

Some pictures and info to go along with Nugatory's reply: Doppler effect, Police RADAR.
 

Suggested for: Speed of Objects

  • Last Post
Replies
3
Views
1K
Replies
8
Views
630
Replies
8
Views
124
  • Last Post
Replies
4
Views
465
Replies
17
Views
829
Replies
8
Views
1K
  • Last Post
Replies
22
Views
7K
Replies
15
Views
349
Top