Answer:
3.8 kg
Explanation:
The torque, <em>τ</em>, due to the force, <em>F</em>, is given by
where <em>r</em> is the radius.
This torque is also given by
where <em>I</em> and <em>α</em> are respectively the moment of inertia and the angular acceleration.
For a solid disk, its moment of inertia for an axis though its centre and perpendicular to its face is given by
where <em>m</em> is its mass and <em>r</em> is its radius.
Hence, we have
Answer:
Vf = 210 [m/s]
Av = 105 [m/s]
y = 2205 [m]
Explanation:
To solve this problem we must use the following formula of kinematics.
where:
Vf = final velocity [m/s]
Vo = initial velocity = 0 (released from the rest)
g = gravity acceleration = 10 [m/s²]
t = time = 21 [s]
Vf = 0 + (10*21)
Vf = 210 [m/s]
Note: The positive sign for the gravity acceleration means that the object is falling in the same direction of the gravity acceleration (downwards)
The average speed is defined as the sum of the final speed plus the initial speed divided by two. (the initial velocity is zero)
Av = (210 + 0)/2
Av = 105 [m/s]
To calculate the distance we must use the following equation of kinematics
44100 = 20*y
y = 2205 [m]