Register to reply

Speed of Objects

by Physics Novice
Tags: objects, speed
Share this thread:
Physics Novice
#1
Sep6-13, 06:48 AM
P: 1
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?
Phys.Org News Partner Physics news on Phys.org
Step lightly: All-optical transistor triggered by single photon promises advances in quantum applications
The unifying framework of symmetry reveals properties of a broad range of physical systems
What time is it in the universe?
Nugatory
#2
Sep6-13, 07:02 AM
Sci Advisor
Thanks
P: 3,752
Quote Quote by Physics Novice View Post
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.
CWatters
#3
Sep6-13, 07:27 AM
P: 3,150
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.

DennisN
#4
Sep6-13, 08:03 AM
DennisN's Avatar
P: 483
Speed of Objects

Quote Quote by Physics Novice View Post
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.


Register to reply

Related Discussions
Objects Speed Introductory Physics Homework 5
Speed of objects Introductory Physics Homework 1
Relative speed between two objects Introductory Physics Homework 1
Objects near the speed of light Special & General Relativity 9
Massive objects going 99.9% speed of light. Special & General Relativity 12