Ask question

Ask question

All categories

2 years ago

7

A21.0-kg block is initially at rest on a horizontal surface. A horizontal force of73.0N is required to set the block in motion,

after which a horizontal force of58.0N is required to keep the block moving with constant speed.(a) Find the coefficient of static friction between the block and the surface.(b) Find the coefficient of kinetic friction between the block and the surface.

1 answer:

Elanso [62]2 years ago

5 0

Answer:

a) μs=0.34

b) μk=0.27

Explanation:

Given that

Mass , m = 21 kg

Force required to move the block ,F= 73 N

The force required to keep the block in motion ,F ' = 58 N

Coefficient of the static friction :

The maximum value of the static friction force

fr= μs m g

At rest position

F= fr

73 = μs x 21 x 10 (take g= 10 m/s²)

$\mu_s=\dfrac{73}{210}$

μs=0.34

Therefore the Coefficient of the static friction will be 0.34.

Coefficient of the kinetic friction ;

Value of the kinetic friction force ,fr= μk m g

F' = Fr

To move the block at constant speed

58 = μs x 21 x 10 (take g= 10 m/s²)

$\mu_k=\dfrac{58}{210}$

μk=0.27

Therefore the Coefficient of the static friction will be 0.27.

You might be interested in

Suppose your network is connected to another network via a router. Which OSI model layer provides the information necessary to d

RUDIKE [14]

Answer: it is called the "NETWORK LAYER"

Explanation: OSI model means Open System Interconnection model. It have different model layers.

The network layer is the OSI model layer that helps in forwarding packets from network to network, using a network router. It's main function is to connect different network together. It also determine the best virtual circuits(paths) for the data to travel.

Because the question specify that the network is connected to a network router, that means the OSI model layer is network layer.

8 0

3 years ago

Answer the three questions below that pertain to atomic orbitals. Part A: No two electrons can have the same set of quantum numb

zimovet [89]

Answer:

Pauli exclusion principle

Explanation:

No two fermions can have the same set of quantum numbers is called the Pauli exclusion principle. And a electron is a fermion.

There are four basic quantum numbers

Principle quantum number n

the angular momentum quantum number l

magnetic quantum number m_l

and electron spin quantum number m_s

8 0

2 years ago

Plzz help! A stationary speed gun emits a

baherus [9]

Answer:

The speed of the baseball is approximately 19.855 m/s

Explanation:

From the question, we have;

The frequency of the microwave beam emitted by the speed gun, f = 2.41 × 10¹⁰ Hz

The change in the frequency of the returning wave, Δf = +3190 Hz higher

The Doppler shift for the microwave frequency emitted by the speed gun which is then reflected back to the gun by the moving baseball is given by 2 shifts as follows;

$\dfrac{\Delta f}{f} = \dfrac{2 \cdot v_{baseball}}{c}$

$\therefore{\Delta f}{} = \dfrac{2 \cdot v_{baseball}}{c} \times f$

Where;

Δf = The change in frequency observed, known as the beat frequency = 3190 Hz

$v_{baseball}$ = The speed of the baseball

c = The speed of light = 3.0 × 10⁸ m/s

f = The frequency of the microwave beam = 2.41 × 10¹⁰ Hz

By plugging in the values, we have;

$\therefore{\Delta f} = 3190 \ Hz = \dfrac{2 \cdot v_{baseball}}{3.0 \times 10^8 \ m/s} \times 2.41 \times 10^{10} \ Hz$

$v_{baseball} = \dfrac{3190 \ Hz \times 3.0 \times 10^8 \ m/s }{2.41 \times 10^{10} \ Hz \times 2} \approx 19.855 \ m/s$

The speed of the baseball, $v_{baseball}$ ≈ 19.855 m/s

3 0

2 years ago

Question 7 of 10

jok3333 [9.3K]

Answer:

when a magnet is hanged freely in air it turns in the direction of the north and south while the magnetic north pole faces the south pole of the earth and magnetic south pole faces the north pole if the earth

4 0

2 years ago

I need someone to give me 2 answers,

yanalaym [24]

Uh.. what's the question..?

8 0

3 years ago