Answer:
The friction force is 250 N
Explanation:
The desk is moving at constant velocity. This means that its acceleration is zero: a = 0. Newton's second law states that the resultant of the forces acting on the desk is equal to the product between mass (m) and acceleration (a):
In this case, we know that the acceleration is zero: a = 0, so also the resultant of the forces must be zero:
(1)
We are only interested in the forces acting along the horizontal direction, since it is the direction of motion. There are two forces acting in this direction:
- the pull, forward, F = 250 N
- the friction force, backward, 
Given (1), we have
So the force of friction must be equal to the pull:
Answer:
correct option is A. Resonance
Explanation:
solution
vibrations in the tube are caused by the Resonance because Resonance cause of sounds production in the musical instrument
As if resonance ( hollow cylindrical tube) immerse in cylinder of water and force in to vibration by tuning fork
As tines of tuning fork vibrate at natural frequency and it create sound wave that impinged up on opening of resonance tube
so correct option is A. Resonance
You can solve this by using Newton's First Law or Newton's Second Law.
1) Newton's First Law or Inertia Law states that in the abscense of a net force acting over an object, this will not chage its state of movement, i.e it will remain at rest (if it is no moving) or with uniform movement (if the object is moving).
2) Newton's Second Law: Net force = mass * acceleration => acceleration = net force / mass = 0 / mass = 0.
Zero accelerations means rest or uniform movement.
First Law is implicit in Second Law.
Answer:
Current flowing in the wire is 1680 A
Explanation:
It is given length of wire l = 3.5 m
Mass of the wire m = 0.03 kg
Magnetic field B = 0.00005 Tesla
Acceleration due to gravity 
Mg force acting on the wire will be equal to Lorentz force acting on the wire.
Therefore 
Therefore current flowing in the wire is 1680 A
