# instantaneous velocity

• Aug 31st 2009, 03:20 PM
BiGpO6790
instantaneous velocity
In a forward punch in karate, the fist begins at rest at the waist and is brought rapidly forward until the arm is fully extended. The speed v(t) of the fist is given in Figure 2-37 for someone skilled in karate. How far has the fist moved at (a) time t = 50 ms and (b) when the speed of the fist is maximum?
http://edugen.wiley.com/edugen/cours...2/fig02_37.gifFig. 2-37
Problem 68.

• Aug 31st 2009, 05:00 PM
artvandalay11
if you integrate velocity, you get distance, this must be well known in any calc class or calc based physics class

since integration is a way to find the area under a curve, you must simply compute the area from 0 to 50

for part b, you have a graph with velocity of the fist and you are looking for the maximum speed of the fist. Speed is the absolute value of velocity, but the velocity is never negative so speed=velocity in this case

can you read the max velocity off of the graph?
• Sep 3rd 2009, 04:23 PM
BiGpO6790
yes the max velocity is 7.5 m/s
• Sep 3rd 2009, 08:56 PM
CaptainBlack
Quote:

Originally Posted by BiGpO6790
In a forward punch in karate, the fist begins at rest at the waist and is brought rapidly forward until the arm is fully extended. The speed v(t) of the fist is given in Figure 2-37 for someone skilled in karate. How far has the fist moved at (a) time t = 50 ms and (b) when the speed of the fist is maximum?
http://edugen.wiley.com/edugen/cours...2/fig02_37.gifFig. 2-37
Problem 68.

Ahh .. now it appears, but so it does not get lost here it is as an upload:

Attachment 12714

CB
• Sep 3rd 2009, 09:05 PM
CaptainBlack
Quote:

Originally Posted by BiGpO6790
In a forward punch in karate, the fist begins at rest at the waist and is brought rapidly forward until the arm is fully extended. The speed v(t) of the fist is given in Figure 2-37 for someone skilled in karate. How far has the fist moved at (a) time t = 50 ms and (b) when the speed of the fist is maximum?
http://edugen.wiley.com/edugen/cours...2/fig02_37.gifFig. 2-37
Problem 68.