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
Ganezh [65]
4 years ago
12

This force can either push the block upward at a constant velocity or allow it to slide downward at a constant velocity. The mag

nitude of the force is different in the two cases, while the directional angle θ is the same. Kinetic friction exists between the block and the wall, and the coefficient of kinetic friction is 0.340. The weight of the block is 51.0 N, and the directional angle for the force is θ = 44.0°. Determine the magnitude of when the block slides (a) up the wall and (b) down the wall.
Physics
1 answer:
sweet-ann [11.9K]4 years ago
3 0

Answer:

Explanation:

Given

coefficient of kinetic friction(\mu _k)=0.34

inclination \theta =44

weight of block=51 N

(a) When block is moving upward friction force acts downward

thus

Fsin\theta -W-f_r=0

as block is moving with constant velocity thus F_{net} is zero

f_r=\mu _kN=0.34\times Fcos\theta

F\left ( \sin \theta -\mu \cos \theta \right )=W

F=\frac{51}{0.45}=113.31 N

(b)When Block slides down the wall friction changes its direction to oppose the block

Fsin\theta -W+f_r=0

F\left ( \sin \theta +\mu \cos \theta \right )=W

F=\frac{W}{\left ( \sin \theta +\mu \cos \theta \right )}

F=\frac{51}{0.939}=54.299 N

You might be interested in
Give 2 reasons for fitting heavy commercial vehicles with many tyres​
forsale [732]
Better weight distribution and more stability
4 0
3 years ago
- A fridge has a maximum static friction force
Dennis_Churaev [7]

Answer:

They will move the fridge if they all push in the same direction, but it will not move with constant velocity

Explanation:

The maximum static friction force is

F_f = -250 N (negative sign since its direction is opposite to the push applied by the people)

Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:

F=130 + 65 +65=260 N

This force is larger than the frictional force, so the fridge will start moving.

However, the net force on the fridge will be:

\sum F = 260 N - 250 N = 10 N

And according to Newton's second law,

\sum F = ma

where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant  velocity.

3 0
4 years ago
In an RC circuit, what fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for
4vir4ik [10]

Answer:

The  fraction fraction of the final energy is stored in an initially uncharged capacitor after it has been charging for 3.0 time constants is  

      k  = 0.903

Explanation:

From the question we are told that

     The time  constant  \tau  =  3

The potential across the capacitor can be mathematically represented as

     V  =  V_o  (1 -  e^{- \tau})

Where V_o is the voltage of the capacitor when it is fully charged

    So   at  \tau  =  3

     V  =  V_o  (1 -  e^{- 3})

     V  =  0.950213 V_o

   Generally energy stored in a capacitor is mathematically represented as

             E = \frac{1}{2 } * C  * V ^2

In this equation the energy stored is directly proportional to the the square of the potential across the capacitor

Now  since capacitance is  constant  at  \tau  =  3

        The  energy stored can be evaluated at as

         V^2 =  (0.950213 V_o )^2

       V^2 =  0.903  V_o ^2

Hence the fraction of the energy stored in an initially uncharged capacitor is  

      k  = 0.903

4 0
3 years ago
Complete the passage to describe the relationship between kinetic energy, internal energy, thermal energy, and
butalik [34]

Answer:

Increases

Increases

Increases

Explanation:

I don't know if you answered your own question but I'll just answer this for others confused ahh

4 0
3 years ago
Read 2 more answers
Which statements about electric field lines are correct? Check all that apply.
slava [35]

Answer:

they cross over one another between charge.

7 0
4 years ago
Other questions:
  • How does energy from an ocean wave power stuff in a house?
    12·1 answer
  • Suppose that the radius of the circular path is r when the speed of the rocket is v and the acceleration of the rocket has magni
    12·1 answer
  • When jogging outside you accidently bump into a curb. Your feet stop but your body continues to move forward and you end up on t
    15·1 answer
  • One day in second grade, Chris drank chocolate milk before recess. She then played hard during recess and got sick from the heat
    9·2 answers
  • In noisy factory environments, it's possible to use a loudspeaker to cancel persistent low-frequency machine noise at the positi
    9·1 answer
  • The foot of a ladder is 6m away from a wall. if the top of the ladder rest 8 feet up on the wall,how long is the ladder?
    5·1 answer
  • How many seconds of space should you keep between you if you're driving a 100 foot truck 30 mph?
    9·1 answer
  • Determine the magnitude of the current flowing through a 4.7 kilo ohms resistor if the voltage across it is (a) 1mV (b) 10 V (c)
    12·1 answer
  • *
    11·1 answer
  • If car is going at a speed of 80 km/h how far will it travel in two hours
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!