Ask question

Ask question

All categories

Nookie1986 [14]

3 years ago

15

A force of 36.0 N is required to start a 3.0-kg box moving across a horizontal concrete floor. Part A) What is the coefficient o

f static friction between the box and the floor? Express your answer using two significant figures. Part B) If the 36.0-N force continues, the box accelerates at 0.54 m/s^2. What is the coefficient of kinetic friction? Express your answer using two significant figures.

1 answer:

matrenka [14]3 years ago

4 0

Answer:

A) 1.2

B) 1.1

Explanation:

A)

F = force required to start the box moving = 36.0 N

m = mass of the box = 3 kg

$F_{g}$ = weight of the box = mg = 3 x 9.8 = 29.4 N

$F_{n}$ = normal force acting on the box by the floor

normal force acting on the box by the floor is given as

$F_{n}$ = $F_{g}$ = 29.4

$F_{s}$ = Static frictional force = F = 36.0 N

$\mu _{s}$ = Coefficient of static friction

Static frictional force is given as

$F_{s}$ = $\mu _{s}$ $F_{n}$

36.0 = $\mu _{s}$ (29.4)

$\mu _{s}$ = 1.2

B)

a = acceleration of the box = 0.54 m/s²

F = force applied = 36.0 N

$f_{k}$ = kinetic frictional force

$\mu _{k}$ = Coefficient of kinetic friction

force equation for the motion of the box is given as

F - $f_{k}$ = ma

36.0 - $f_{k}$ = (3) (0.54)

$f_{k}$ = 34.38 N

Coefficient of kinetic friction is given as

$\mu _{k}=\frac{f_{k}}{F_{n}}$

$\mu _{k}=\frac{34.38}{29.4}$

$\mu _{k}$ = 1.1

You might be interested in

Lincoln weighs 400 newtons. What’s his mass rounded to the nearest kilogram? Assume that acceleration due to gravity is 9.8 N/kg

Yanka [14]

Weight equals mass times gravitational acceleration=400N, so mass=400/9.8=41kg approx.

6 0

3 years ago

Read 2 more answers

Two identical loudspeakers are placed on a wall 1.00 m apart. A listener stands 4.00 m from the wall directly in front of one of

natita [175]

Answer:

The phase difference is 0.659 rad.

Explanation:

Given that,

Distance between two identical loudspeakers d= 1.00 m

Distance between speakers and listener r= 4.00 m

Frequency = 300 Hz

Suppose we need to find the phase difference in radian between the waves from the speakers when they reach the observer

We need to calculate the r'

Using Pythagorean theorem

$r'=\sqrt{d^2+r^2}$

Where, d = distance between two identical loudspeakers

r = distance between speakers and listener

Put the value into the formula

$r'=\sqrt{(1.00)^2+(4.00)^2}$

$r'=\sqrt{1.00+16.00}$

$r'=4.12\ m$

We need to calculate the path difference

Using formula of path difference

$|r'-r|=4.12-4.00$

$|r'-r|=0.12\ m$

We need to calculate the wavelength

Using formula of wavelength

$\lambda=\dfrac{v}{f}$

Where, v = speed of sound

f = frequency

Put the value into the formula

$\lambda=\dfrac{343}{300}$

$\lambda=1.143\ m$

We need to calculate the phase difference

Using formula of phase difference

$\phi=\dfrac{2\pi\times|r'-r| }{\lambda}$

$\phi=\dfrac{2\pi\times0.12}{1.143}$

$\phi=0.659\ rad$

Hence, The phase difference is 0.659 rad.

7 0

3 years ago

(Brainliest Question)

coldgirl [10]

The electromagnetic spectrum is the range of all types of radiation. Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.

To help you, check out the picture!

6 0

3 years ago

Which of newton’s laws best explains why motorists should buckle up?

ivann1987 [24]

Newton's first law of motion.

4 0

2 years ago

Water (rhoH20 = 1000.0 kg/m3 ) flows through a garden hose that goes up a step 20.0 cm high. The cross-sectional area of the hos

Soloha48 [4]

Answer:

P₂ = 138.88 10³ Pa

Explanation:

This is a problem of fluid mechanics, we must use the continuity and Bernoulli equation

Let's start by looking for the top speed

Q = A₁ v₁ = A₂ v₂

We will use index 1 for the lower part and index 2 for the upper part, let's look for the speed in the upper part (v2)

v₂ = A₁ / A₂ v₁

They indicate that A₂ = ½ A₁ and give the speed at the bottom (v₁ = 1.20 m/s)

v₂ = 2 1.20

v₂ = 2.40 m / s

Now let's write the Bernoulli equation

P₁ + ½ ρ v₁² + ρ g y₁ = P2 + ½ ρ v₂² + ρ g y₂

Let's clear the pressure at point 2

P₂ = P₁ + ½ ρ (v₁² - v₂²) + ρ g (y₁-y₂)

we put our reference system at the lowest point

y₁ - y₂ = -20 cm

Let's calculate

P₂ = 143 10³ + ½ 1000 (1.20² - 2.40²) + 1000 9.8 (-0.200)

P₂ = 143 103 - 2,160 103 - 1,960 103

P₂ = 138.88 10³ Pa

3 0

3 years ago