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,

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2