Answer:
The Answer is C. the student changed too many variables.
Explanation:
For the quiz in K12
Answer:
A _commutator_ is used in a motor to switch the direction of the magnetic field created by the current.
The rotating part of a motor that holds the electromagnets is called the __armature___.
Electric current passes through the _brushes_ and into the electromagnets in an electric motor.
A motor turns _electrical_ energy into _mechanical_ energy.
Explanation:
A commutator, which is a split ring rotary switching device, reverses the direction of the current between the external circuit and the rotor. Reversing the current reverses the magnetic field.
The armature comprises the rotating part of the motor and the electromagnets
A brush is the electrical contact for conducting current through the moving and stationary parts of an electric motor
An electric motor turns electrical energy into mechanical energy.
Answer:
The object in a uniform motion covers same distances in an equal time period. Objects in a non-uniform motion cover dissimilar distances in an equal time period.
Explanation:
The speed of the object traveling in uniform motion is constant, the actual speed and the average speed of the moving body is same.
Answer:(a)360N,(b)171N,(c)2.702m
Explanation:
(a)Maximum Friction Force =
=360 N
(b)Moment about Ground Point
(c)
Here maximum friction force can be 360 N
Therefore 
Where x is the maximum distance moved by man along the ladder
740x=2000
x=2.702m
Answer:
the velocity of the bullet-wood system after the collision is 2.48 m/s
Explanation:
Given;
mass of the bullet, m₀ = 20 g = 0.02 kg
velocity of the bullet, v₀ = 250 m/s
mass of the wood, m₁ = 2 kg
velocity of the wood, v₁ = 0
Let the velocity of the bullet-wood system after collision = v
Apply the principle of conservation of linear momentum to calculate the final velocity of the system;
Initial momentum = final momentum
m₀v₀ + m₁v₁ = v(m₀ + m₁)
0.02 x 250 + 2 x 0 = v(2 + 0.02)
5 + 0 = v(2.02)
5 = 2.02v
v = 5/2.02
v = 2.48 m/s
Therefore, the velocity of the bullet-wood system after the collision is 2.48 m/s
