Responding to an alarm, a 100 kg, a fireman slides down a pole to the ground floor, 3.1 m below. The fireman starts at rest and lands with a speed of 3.8 m/s.
Find the average force exerted on the fireman by the pole.
Find the average force exerted on the fireman when the landing speed is 1.9 m/s.
Ok, first of all, this is the force of gravity acting against fricion
Net force= ma
mg-friction=ma
Now, you can find a
a=(Vf-Vi)/t where t is timedown. But t= height/avgvelocity = 2*height/Vf
now that you have a,
then find friction force
for each speed.
To find the average force exerted on the fireman by the pole, we can use the work-energy principle. The work done by the force of friction between the fireman and the pole is equal to the change in the fireman's kinetic energy. The work done by the force of friction is equal to the force of friction multiplied by the distance traveled. The change in kinetic energy is equal to the final kinetic energy minus the initial kinetic energy.
1. Find the initial kinetic energy of the fireman:
The fireman starts at rest, so the initial kinetic energy is zero.
2. Find the final kinetic energy of the fireman:
The final kinetic energy of the fireman is given by 0.5 * mass * velocity^2.
Plugging in the given values: final kinetic energy = 0.5 * 100 kg * (3.8 m/s)^2.
3. Calculate the change in kinetic energy:
Change in kinetic energy = final kinetic energy - initial kinetic energy.
4. Find the distance traveled:
The distance traveled is given as 3.1 m.
5. Calculate the force of friction:
The force of friction is equal to the work done divided by the distance traveled.
Force of friction = change in kinetic energy / distance traveled.
Now we can use this general method to find the average force in both scenarios:
Scenario 1: Landing speed is 3.8 m/s (given)
Scenario 2: Landing speed is 1.9 m/s
1. Follow steps 1-5 to calculate the force in scenario 1.
2. Adjust the final velocity in step 2 for scenario 2 and repeat steps 2-5 to calculate the force in scenario 2.
By applying this method, you can find the average force exerted on the fireman by the pole in both scenarios.