Answer:
magnitude of the frictional torque is 0.11 Nm
Explanation:
Moment of inertia I = 0.33 kg⋅m2
Initial angular velocity w° = 0.69 rev/s = 2 x 3.142 x 0.69 = 4.34 rad/s
Final angular velocity w = 0 (since it stops)
Time t = 13 secs
Using w = w° + §t
Where § is angular acceleration
O = 4.34 + 13§
§ = -4.34/13 = -0.33 rad/s2
The negative sign implies it's a negative acceleration.
Frictional torque that brought it to rest must be equal to the original torque.
Torqu = I x §
T = 0.33 x 0.33 = 0.11 Nm
Answer:48.2 Joules
Explanation:
Given
two masses of 0.2 kg and 0.4 kg collide with each other
after collision 0.2 kg deflect 30 north of east and 0.4 kg deflects 53.1 south of east
Velocity of 0.2 kg mass is
Velocity of 0.4 kg mass
Thus total Kinetic energy 
Kinetic energy=48.2 J
Answer:
Emf induced i equal to 329.4 volt
Explanation:
Note : Here i think we have to find emf induced in the coil
Number of turns in the coil N= 180
Sides of square d = 30 cm = 0.3 m
So area of the square 
Magnetic field is changes from 0 to 1.22 T
Therefore 
Time interval in changing the magnetic field dt = 0.06 sec
Induced emf is given by
Answer:
Regular reflection
Explanation:
- Reflection is the phenomenon that occurs when a light wave hits the interface between two different mediums and it bounces off back into the same medium. The angle of reflection (measured between the reflected ray and the perpendicular to the interface) is equal to the angle of incidence (measured between the incident ray and the perpendicular to the interface).
There are two different types of reflection:
- Regular reflection: this occurs when the interface between the two mediums is smooth (such as in the case of the still lake), so all the parallel light waves (which have same angle of incidence) are reflected exactly with the same angle of reflection (so, they come out all with same direction)
- Diffuse reflection: this occurs when the interface between the two mediums is not smooth, so each light ray is reflected with a different angle because it hits the interface with a different angle of incidence.
Therefore, in the case of the still lake, the correct answer is regular reflection.
Answer: False
Explanation:
Relative to the concept of radiations, a black body is an object capable of absorbing any form of electromagnetic radiation irrespective of its frequency or angle of incidence when incident on such object.
However, the same cannot be said about real bodies as real bodies are those which reflect all rays incident on them completely and uniformly in all directions.
One very important characteristic of black bodies is that they are ideal emmiters.
The concept of emmisivity is brought about by the existence of real bodies .
This is due to the fact that they are only able to emit radiation at a fraction of the black body energy levels.
Please note that by convention, the emmisivity of a real body is always less thaan 1.
As such they are not able to emit as much radiation as a black body at the same temperature.
