Amotor drives a disk initially at rest through 25.9 rotations in 5.0 s. assume the vector sum of the torques caused by the force exerted by the motor and the force of friction is constant. the rotational inertia of the disk is 4.0 kg⋅m2. when the motor is switched off, the disk comes to rest in 12 s.
a.)what is the magnitude of torque created by the force of friction?
b.)what is the magnitude of torque caused by the force exerted by the motor?

Answer

given,

rotation of disk is equal to(θ) = 25.9

time taken = 5 s

moment of inertia of disk = 4 Kg.m²

disk come to rest in = 12 sec

a)  θ = 2 π x 25.9

    θ = 162.73 rad

    using equation of rotational motion

     θ =  ω₀t + 0.5 α t²

     162.79 =  0 + 0.5 x α x 5²

      α = 13.02 rad/s²

total torque acting

again using the rotational equation

when only friction is acting angular acceleration

now torque due to friction

now,

28. evolution

29. environment, survive, offspring  

explanation:

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.