Lost on this Physics Question for Homework
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Lost on this Physics Question for Homework

[From: ] [author: ] [Date: 12-02-11] [Hit: ]
(a) Find the average force exerted on the fireman by the pole.Answer in N (b) If the landing speed is half that in part (a), is the average force exerted on the fireman doubled? yes or no? (c) Find the average force exerted on the fireman when the landing speed is 1.85 m/s.......
Responding to an alarm, a 80 kg fireman slides down a pole to the ground floor, 3.2 m below. The fireman starts at rest and lands with a speed of 3.7 m/s.

(a) Find the average force exerted on the fireman by the pole.
Answer in N

(b) If the landing speed is half that in part (a), is the average force exerted on the fireman doubled?
yes or no ?



(c) Find the average force exerted on the fireman when the landing speed is 1.85 m/s.

Answer in N

Can some help?

-
Acceleration due to gravity = 9.81 m/s^2
Force on fireman due to gravity
= 80 * 9.81 = 784.8 N

a)
v^2 = u^2 + 2as
3.7^2 = 0^2 + 2a*3.2

a = 3.7^2 / (2 * 3.2) = 2.1390625 m/s^2

Net force accelerating fireman down the pole
= 2.1390625 * 80 = 171.125 N

Average force exerted by the pole on the fireman
= 784.8 - 171.125 = 613.675 N

b)
NO

c)
1.85^2 = 2a*3.2
a = 1.85^2 / (2 * 3.2)
= 0.534765625 m/s^2

Net force accelerating the fireman down the pole
= 0.534765625 * 80 = 48.78125 N

Average force exerted on fireman by the pole
= 784.8 - 48.78125 = 742.01875 N
1
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