Friday

September 19, 2014

September 19, 2014

Posted by **HELP!!!!** on Thursday, March 17, 2011 at 7:19pm.

(a) How long does it take the discus thrower's speed to get to 4.5 rad/s?

(b) How many revolutions does the thrower make to reach the speed of 4.5 rad/s?

revolutions

(c) What is the linear speed of the discus at 4.5 rad/s?

(d) What is the tangential acceleration of the discus thrower at this point?

(e) What is the magnitude of the centripetal acceleration of the discus thrown?

(f) What is the magnitude of the discus's total acceleration?

- physics -
**bobpursley**, Thursday, March 17, 2011 at 7:22pmI will be happy to critique your thinking on this.

- physics -
**HELP!!!!**, Thursday, March 17, 2011 at 7:37pma) 4.5/3= 1.5 s

b) i'm still confused of how to get the number of revolutions

c) a=v^2/r the answer is 5.4 m/s

d) at=r alpha but we need to find alpha first to get at

- physics -
**bobpursley**, Thursday, March 17, 2011 at 7:41pmb, displacement= 1/2 angacceleration*time^2

c. Your answer is nonsense. Tangential velocty = angularvelocity*r

d.total acceleartion: find centripetal acceleration (v^2/r) That is inward. No tangentail acceleration is 3*r

those are at ninety degrees, add them as vectors (Pythagorean theorem_

- physics -
**HELP!!!!**, Thursday, March 17, 2011 at 7:57pmi just want to find the number of revolutions , i know that 2 pi rad= 1 rev but how do we find that in this question.

**Answer this Question**

**Related Questions**

physics - A discus thrower (with arm length of 1.2 m) starts from rest and ...

Physics - A discus thrower (with arm length of 1.2 m) starts from rest and ...

physics - The flywheel of a steam engine begins to rotate from rest with a ...

Physics - The flywheel of a steam engine begins to rotate from rest with a ...

physics - The flywheel of a steam engine begins to rotate from rest with a ...

physics help please.... - After fixing a flat tire on a bicycle you give the ...

Physics - You are riding a merry-go-round on the rim which is turning ...

Physics - A rotating wheel requires 8.00 s to rotate 29.0 revolutions. Its ...

physics - Starting from rest at t = 0 s, a wheel undergoes a constant angular ...

physics - Starting from rest at t = 0 s, a wheel undergoes a constant angular ...