Physics, 07.07.2019 21:00 quentonwise

An 80-kg fireman slides 5.0m down a fire pole. he holds the pole, which exerts a 500-n steady resistive force on thr fireman. at the bottom he slows to a stop in 0.40m by bending his knees. what can you determine using thos information?

Answers: 1

Show answers

Answers

Answer from: rosyarellano101127

Quite a few things can be determined using this information.

(i) First, we can calculate the Weight of the fireman using W = mg.

We get its magnitude as W = (80)(9.8) = 784 N

(ii) While his Weight is responsible for pulling him down, the pole exerts a constant Resistive Force that is given to be 500 N.

We can calculate the Net Force acting on the fireman as

$F_{net} = W - Resistive Force$

We get its numerical value to be $F_{net} = 284N$

(iii) Using this, we can calculate the acceleration with which he slides down the pole from Newton's 2nd law equation as

$F_{net} =ma$

Therefore, $a = \frac{284}{80} =3.55 m/s^{2}$

(iv) With this acceleration, he slides down a distance of 5.0 m - 0.4 m = 4.6 m before he starts applying an additional force with his knees.

We can calculate the velocity he attains just before bending his knees using the following data:

Initial Velocity at the top of the pole $V_{i} =0$

Vertical displacement down the pole D = 4.6 m

Acceleration $a = 3.55 m/s^{2}$

Final Velocity $V_{f} = ?$

Using the equation $V^{2} _{f} =V^{2} _{i} +2aD$

Plugging in the numbers, we have $V^{2} _{f} =0+2(3.55)(4.6)$

Thus, we get the value of $V_{f}$ as 5.72 m/s

(v) This velocity serves as the initial velocity for the part of the journey with his knees bent.

We can calculate the acceleration he has using the following data:

Initial Velocity $V_{i}=5.72$ m/s

Final Velocity $V_{f} =0$

Displacement during the last part of the journey D = 0.4 m

Acceleration a = ?

Again using the equation $V^{2} _{f} =V^{2} _{i} +2aD$ , and plugging in the known numbers, we get

$(0)^{2} =(5.72)^{2} +2(a)(0.4)$

Hence, $a=-40.898 m/s^{2}$

(vi) We can calculate the Net Force acting on him during this part of the journey as

$F_{net} =(80)(-40.898)=-3271.84N$

(vii) Since the Net Force is the vector sum of Weight, Resistive Force, and the additional Knee Force, we can write them as

W-Resistive Force-Knee Force=-3271.84N

Solving for Knee Force gives its magnitude to be 3555.84 N.

Thus, the fireman begins applying an additional 3,556 N force to stop himself in 0.4 m.

(viii) We can even calculate the time taken for the entire journey. We will deal with it in two parts.

For part one, the following information can be used:

Initial Velocity $V_{i} =0$

Final Velocity $V_{f} =5.72m/s$

Acceleration $a = 3.55m/s^{2}$

Time taken t = ?

Using the equation $V_{f} =V_{i} +at$ , we get the time taken as 1.6 seconds.

For the second part of the journey, the following information can be used:

Initial Velocity $V_{i} =5.72m/s$

Final Velocity $V_{f} =0$

Acceleration $a=-40.898m/s^{2}$

Time taken t = ?

Using the equation $V_{f} =V_{i} +at$ again, and plugging in the appropriate values, we get the time taken as 0.14 seconds.

Hence, the total time the fireman took to slide down the 5.0 m pole is 1.74 seconds.

Hope this helps!

Answer from: Quest

Ihope you find the answer

Answer from: Quest

no. bullets are macro objects. wave nature is for light waves, extremely tiny particles. if a light particle was the size of your finger, the bullet would be the size of the universe. so basically, that huge difference in size makes the wave nature of matter insignificant.

Another question on Physics

Physics, 22.06.2019 06:00

Why don't you see your reflection in water with waves or repples

Answers: 1

Answer

Physics, 22.06.2019 07:30

Quantum mechanics applies to subatomic, atomic, nanometer-size, and micrometer-size systems. nanometer, micrometer, and kilometer-size systems. atomic, nanometer-size, and micrometer-size systems. subatomic, atomic, and nanometer-size systems.

Answers: 2

Answer

Physics, 22.06.2019 09:30

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

Answers: 3

Answer

Physics, 22.06.2019 18:20

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped

Answers: 2

Answer

You know the right answer?

An 80-kg fireman slides 5.0m down a fire pole. he holds the pole, which exerts a 500-n steady resist...

Questions