PLEASE HELP:( urgent!!

A 25kg chair initially at rest on a horizontal floor requires a 165 N horizontal force to set it in motion. Once the chair is in

SCORPION-xisa [38]

Answer:

$\mu_k=0.51$

Explanation:

Given that

Mass , m = 25 kg

We know that when body is in rest condition then static friction force act on the body and when body is in motion the kinetic friction force act on the body .That is why these two forces are given as follows

Static friction force ,fs= 165 N

Kinetic friction force ,fk = 127 N

If the body is moving with constant velocity ,it means that acceleration of that body is zero and all the forces are balanced.

Lets take coefficient of kinetic friction = μk

The kinetic friction is given as follows

fk = μk m g

Now by putting the values

127 = μk x 25 x 9.81

$\mu_k=\dfrac{127}{25\times 9.81}$

$\mu_k=0.51$

Therefore the value of coefficient of kinetic friction will be 0.51

4 0

3 years ago

Show that the effective force constant of a series combination is given by 1keff=1k1+1k2. (Hint: For a given force, the total di

S_A_V [24]

Answer:

1keff=1k1+1k2

see further explanation

Explanation:for clarification

Show that the effective force constant of a series combination is given by 1keff=1k1+1k2. (Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination. Also, each spring must exert the same force. Do you see why?

From Hooke's law , we know that the force exerted on an elastic object is directly proportional to the extension provided that the elastic limit is not exceeded.

Now the spring is in series combination

F $\alpha$ e

F=ke

k=f/e.........*

where k is the force constant or the constant of proportionality

k=f/e

$f_{eff} =f_{1} +f_{2}$ ............................1

also for effective force constant

divide all through by extension

1) Total force is

Ft=F1+F2

Ft=k1e1+k2e2

F = k(e1+e2) 2)

Since force on the 2 springs is the same, so

k1e1=k2e2

e1=F/k1 and e2=F/k2,

and e1+e2=F/keq

Substituting e1 and e2, you get

1/keq=1/k1+1/k2

Hint: For a given force, the total distance stretched by the equivalent single spring is the sum of the distances stretched by the springs in combination.

4 0

3 years ago

A 25.0-kg test rocket is fired vertically. When the engine stops firing, the rocket’s kinetic energy is 2017 J. After the fuel i

Dahasolnce [82]

Answer:

1. 2.12105 J. The final kinetic energy is. KE f mv2. (875.0 kg)(44.0 m/s)2 2.What is the velocity of the two hockey players after the collision? ... A 10.0-kg test rocket is fired vertically from.

Explanation:

Sana maka tulong

6 0

3 years ago

A microphone is attached to a spring that is suspended from the ceiling, as the drawing indicates. Directly below on the floor i

svet-max [94.6K]

Answer:

$0.261\ \text{m}$

Explanation:

$\Delta f$ = Change in frequency = 2.1 Hz

$f$ = Frequency of source of sound = 440 Hz

$v_m$ = Maximum of the microphone

$v$ = Speed of sound = 343 m/s

$T$ = Time period = 2 s

We have the relation

$\Delta f=2f\dfrac{v_m}{v}\\\Rightarrow v_m=\dfrac{\Delta fv}{2f}\\\Rightarrow v_m=\dfrac{2.1\times 343}{2\times 440}\\\Rightarrow v_m=0.8185\ \text{m/s}$

Amplitude is given by

$A=\dfrac{v_m T}{2\pi}\\\Rightarrow A=\dfrac{0.8185\times 2}{2\pi}\\\Rightarrow A=0.261\ \text{m}$

The amplitude of the simple harmonic motion is $0.261\ \text{m}$ .

4 0

3 years ago

It takes a student 12.0 minutes to get home from school while riding their bike at 6.7 m/s.

givi [52]

Answer: 289.44km

Explanation:

4 0

4 years ago