Answer:
a) 
, b) 
Explanation:
The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:
Where 
is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:
Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:
a) t = 50 s.
b) t = 100 s.
Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:
Since 
, then the angular velocity is equal to zero. Therefore:
Answer:
Time taken, 
Explanation:
It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.
From the figure,
The sum of forces in y direction is :
Sum of forces in x direction,
.............(1)
Also, 
Equation (1) becomes :
...............(2)
Let t is the time taken for the ball to rotate once around the axis. It is given by :
Put the value of T from equation (2) to the above expression:
On solving above equation :
Hence, this is the required solution.
Photons are particles of electromagnetic radiation.
Answer:
Explanation:
Given that,
Mass of sledge hammer;
Mh =2.26 kg
Hammer speed;
Vh = 64.4 m/s
The expression fot the kinetic energy of the hammer is,
K.E(hammer) = ½Mh•Vh²
K.E(hammer) = ½ × 2.26 × 64.4²
K.E ( hammer) = 4686.52 J
If one forth of the kinetic energy is converted into internal energy, then
ΔU = ¼ × K.E(hammer)
∆U = ¼ × 4686.52
∆U = 1171.63 J
Thus, the increase in total internal energy will be 1171.63 J.
Answer:
r = 58.44 [m]
Explanation:
To solve this problem we must use the following equation that relates the centripetal acceleration with the tangential velocity and the radius of rotation.
a = v²/r
where:
a = centripetal acceleration = 15.4 [m/s²]
v = tangential speed = 30 [m/s]
r = radius or distance [m]
r = v²/a
r = 30²/15.4
r = 58.44 [m]
