Answer:
D
Explanation:
From the information given:
The angular speed for the block 
Disk radius (r) = 0.2 m
The block Initial velocity is:
Change in the block's angular speed is:
However, on the disk, moment of inertIa is:
The time t = 10s
∴
Frictional torques by the wall on the disk is:
Finally, the frictional force is calculated as:
Answer:
u/2 √(1 + 3 cos² θ)
Explanation:
The object is thrown at an angle θ, so the velocity has two components, vertical and horizontal.
Initially, the vertical component is u sin θ and the horizontal component is u cos θ.
At the maximum height, the vertical component is 0 and the horizontal component is u cos θ.
The mean vertical velocity is:
(u sin θ + 0) / 2 = u/2 sin θ
The mean horizontal velocity is:
(u cos θ + u cos θ) / 2 = u cos θ
The net mean velocity can be found with Pythagorean theorem:
v² = (u/2 sin θ)² + (u cos θ)²
v² = u²/4 sin² θ + u² cos² θ
v² = u²/4 (1 − cos² θ) + u² cos² θ
v² = u²/4 (1 − cos² θ) + u²/4 (4 cos² θ)
v² = u²/4 (1 − cos² θ + 4 cos² θ)
v² = u²/4 (1 + 3 cos² θ)
v = u/2 √(1 + 3 cos² θ)
No, it will not fall. The pencil will remain at zero speed relative to the spacecraft and will orbit the earth with the spacecraft.
Answer:
Workdone = 2906.25J
Explanation:
Given the following data;
Force, F = 155
Distance, d = 0.75
Stroke, s = 25
Mathematically, work done is given by the formula;
Work done = force * distance * stroke
Where,
W is the work done
F represents the force acting on a body.
d represents the distance covered by the body.
s is the number of strokes.
Substituting into the equation, we have;
Workdone = 2906.25J
As a transformer generates ac current of different voltage when the switch is closed and the current flows in the primary coil which induces a magnetic field.
Answer: Option 2
<u>Explanation:</u>
A transformer is an electric device which can vary the potential differences or voltages of an alternating current. It's a simple device composed of an iron core, a primary and the secondary current conducting coil.
The primary coil is attached to the switch which provides ac current through potential difference. Now this current induces a magnetic field in the iron core. When the voltage of this ac current is varied, the magnetic field varies and starts inducing ac current of different voltage in the secondary coil.
Thus, an AC current of different voltage flows in the secondary coil that can be used in small electric devices. This is how a transformer works. There are two kinds of transformers- Step Up and Step Down. A step up transformer increases the potential difference whereas the step down does the opposite.
