Answer:
The magnitude of the average angular acceleration is calculated as
Explanation:
Maximum speed that can be attained by the disk, = 10,000 rpm
Speed of spinning of the disk, N = 7570 rpm
Time taken to come to rest, t = 0.435 s
Now,
The initial angular velocity is given by:
Final angular velocity,
The average angular acceleration of the disk can be computed by using the kinematic eqn:
Answer:
5.7 m
Explanation:
AD = length of the ladder = L = 8 m
AB = distance of the center of mass of the ladder = (0.5) L = (0.5) 8 = 4 m
AC = distance of person on the ladder from the bottom end = x
W = weight of the ladder = 240 N
= weight of the person = 710 N
F = force by the wall on the ladder
N = normal force by ground on the ladder = ?
Using equilibrium of force along the vertical direction
N = + W
N = 710 + 240
N = 950 N
μ = Coefficient of static friction = 0.55
f =static frictional force on the ladder
Static frictional force is given as
f = μ N
f = (0.55) (950)
f = 522.5 N
Force equation along the horizontal direction is given as
F = f
F = 522.5 N
using equilibrium of torque about point A
F Sin50 (AD) = W Cos50 (AB) + ( Cos50 (AC))
(522.5) Sin50 (8) = (240) Cos50 (4) + (710) Cos50 (x)
x = 5.7 m
Here As we can see the figure that the end of the rope is pulled by some force F
Now as we can see that Piano is connected by a pulley which is passing over the pulley so effectively net force on the piano upwards will be 2F as it is connected by 2 ropes by the pulley
Now for constant velocity of the piano we will say
since velocity is constant so acceleration must be ZERO
so here we have
as we know here that
mg = 1000 N
so we will have
so here force must be 500 N