1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
vladimir1956 [14]
3 years ago
7

A 25kg chair initially at rest on a horizontal floor requires 165 N force to set it in motion. Once the chair is in motion, a 12

7 N horizontal force keeps it moving at a constant velocity. Find the coefficient of static friction between the chair and the floor.
Physics
1 answer:
bazaltina [42]3 years ago
3 0

The coefficient of static friction between the chair and the floor is 0.67

Explanation:

Given:

Weight of the chair = 25kg

Force = 165 N (F_applied)

Force = 127 N (F_max)

To find: Coefficient of static friction  

The “coefficient of static friction” between a chair and the floor is defined as the ration of maximum force to the normal force acting on the chair  

μ_s=F_{max}/F_{n}  

The F_n is equal to the weight multiplied by its gravity

∴F_{n}=mg  

Thus the coefficient of static friction changes as

μ_s=F_{max}/mg

μ_{s} = =165N/((25kg)\times(9.80 m/s^2 ) )

= 0.67

You might be interested in
A beaker has a mass of 125g. What is the mass of this beaker in decigrams
Anit [1.1K]
1250 decigrams
1 gram = 10 decigrams
4 0
3 years ago
Can the velocity of a body revese the direction when acceleration is constant?
TEA [102]

Answer:

Yes, the velocity of the object can reverse direction when its acceleration is constant. For example consider that the velocity of any object at any time t is given as: ... At At t = 0 sec, the magnitude of velocity is 2m/s and is moving in the forward direction i.e.v (t) = -2.

7 0
3 years ago
1,What were you doing when you felt most passionate and alive?
Luba_88 [7]

Answer:

wen I was in the car toing home from school after a bad day n si si I have crazzyyy

4 0
2 years ago
Read 2 more answers
In 1999, Robbie Knievel was the first to jump the Grand Canyon on a motorcycle. At a narrow part of the canyon (65 m wide) and t
vfiekz [6]

Answer:

His launching angle was 14.72°

Explanation:

Please, see the figure for a graphic representation of the problem.

In a parabolic movement, the velocity and displacement vectors are two-component vectors because the object moves along the horizontal and vertical axis.

The horizontal component of the velocity is constant, while the vertical component has a negative acceleration due to gravity. Then, the velocity can be written as follows:

v = (vx, vy)

where vx is the component of v in the horizontal and vy is the component of v in the vertical.

In terms of the launch angle, each component of the initial velocity can be written using the trigonometric rules of a right triangle (see attached figure):

sin angle = opposite / hypotenuse

cos angle = adjacent / hypotenuse

In our case, the side opposite the angle is the module of v0y and the side adjacent to the angle is the module of vx. The hypotenuse is the module of the initial velocity (v0). Then:

sin angle = v0y / v0  then: v0y = v0 * sin angle

In the same way for vx:

vx = v0 * cos angle

Using the equation for velocity in the x-axis we can find the equation for the horizontal position:

dx / dt = v0 * cos angle

dx = (v0 * cos angle) dt (integrating from initial position, x0, to position at time t and from t = 0 and t = t)

x - x0 = v0 t cos angle

x = x0 + v0 t cos angle

For the displacement in the y-axis, the velocity is not constant because the acceleration of the gravity:

dvy / dt = g ( separating variables and integrating from v0y and vy and from t = 0 and t)

vy -v0y = g t

vy = v0y + g t

vy = v0 * sin angle + g t

The position will be:

dy/dt = v0 * sin angle + g t

dy = v0 sin angle dt + g t dt (integrating from y = y0 and y and from t = 0 and t)

y = y0 + v0 t sin angle + 1/2 g t²

The displacement vector at a time "t" will be:

r = (x0 + v0 t cos angle, y0 + v0 t sin angle + 1/2 g t²)

If the launching and landing positions are at the same height, then the displacement vector, when the object lands, will be (see figure)

r = (x0 + v0 t cos angle, 0)

The module of this vector will be the the total displacement (65 m)

module of r = \sqrt{(x0 + v0* t* cos angle)^{2} }  

65 m = x0 + v0 t cos angle ( x0 = 0)

65 m / v0 cos angle = t

Then, using the equation for the position in the y-axis:

y = y0 + v0 t sin angle + 1/2 g t²

0 =  y0 + v0 t sin angle + 1/2 g t²

replacing t =  65 m / v0 cos angle and y0 = 0

0 = 65m (v0 sin angle / v0 cos angle) + 1/2 g (65m / v0 cos angle)²  

cancelating v0:

0 = 65m (sin angle / cos angle) + 1/2 g * (65m)² / (v0² cos² angle)

-65m (sin angle / cos angle) = 1/2 g * (65m)² / (v0² cos² angle)  

using g = -9.8 m/s²

-(sin angle / cos angle) * (cos² angle) = -318.5 m²/ s² / v0²

sin angle * cos angle = 318.5 m²/ s² / (36 m/s)²

(using trigonometric identity: sin x cos x = sin (2x) / 2

sin (2* angle) /2 = 0.25

sin (2* angle) = 0.49

2 * angle = 29.44

<u>angle = 14.72°</u>

3 0
3 years ago
The average power dissipated by a resistor connected to a sinusoidal emf is 5.0 W.
loris [4]

I this is tricky one sec.. I would go with b

4 0
3 years ago
Other questions:
  • The space shuttle travels at about 28,000 km per hour. Using that information, estimate how many hours it will take the shuttle
    11·1 answer
  • Individuals who smoke will have a higher frequency of developing cancer later in life.
    5·1 answer
  • Which is one way that scientists ensure that data is reliable?
    14·1 answer
  • What does the symbol for Monday mean???
    6·1 answer
  • A torque of 12 N*m is applied to a solid uniform disk of radius 0.50 m. If the disk accelerates at 2.6 rad/s^2 what is the mass
    12·1 answer
  • When an object moves in a circular path, it accelerates toward the center of the circle as a result of ______.
    15·1 answer
  • The ability to attract electrons is known as:
    14·1 answer
  • The particles of a more dense substance are closer together
    14·2 answers
  • A machine used an input force of 200 N to produce an output force of 800N. What is the mechanical advantage of this machine?
    7·2 answers
  • Which of jupiter’s moons is the largest moon in the solar system?.
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!