Torque
Define torque
a force applied to rotate an object
define an object in rotational equilibrium
net torque is zero
Why does increasing the length of a wrench increases the torque?
it increases the level arm
A net torque applied to an object will always cause it to do what?
rotate
A student applies a force of 40 N perpendicularly to a door handle located 0.8 m from the door's hinge. What is the magnitude of the torque applied to the door?
32 Nm
Give the torque equation that does not use Rotational Inertia.
Torque = Force*level arm
A rotating object spins about the "axis of ___."
rotation
What is the rate at which an object's angular velocity changes over time, essentially how quickly its rotation speeds up or slows down
angular acceleration
To convert from angular quantities to tangential quantities, what should you do?
multiple by the radius
A force of 20 N is applied to a wrench handle 0.5 m from the bolt (the pivot). If the force is applied at an angle of 30∘ with respect to the handle (the lever arm), what is the magnitude of the torque produced?
5 Nm
What angle should you apply a force to produce the most torque?
90 degrees
Which one of Newton's Laws applies to an object that is in rotational equilibrium
N1L
rotational equivalent of mass
moment of inertia
Two ladybugs are on a spinning disk. One lady bug is closer to the center of the disk, and the other is closer to the edge of the disk. How do their linear velocities compare?
the one closer to the center has a smaller linear velocity.
A wheel starts from rest and accelerates at 2 rad/s2 for 5 seconds. Find its angular displacement.
25 rad
Which direction is considered positive for an object that is rotating?
counterclockwise
Two kids are on a seesaw one is 80 kg and is sitting 0.3 m from the pivot, where will the other kid (60 kg) need to sit in order for them to be in equilibrium.
0.4 m
How are torque and angular acceleration related?
directly
Two ladybugs are on a spinning disk. One lady bug is closer to the center of the disk, and the other is closer to the edge of the disk. How do their angular velocities compare?
they are the same
A grinding stone starts with an angular velocity of ωi=4.0 rad/s and uniformly accelerates to a final angular velocity of ωf=16.0 rad/s over a period of 3.0 s. What is the angular acceleration of the grinding stone?
4 rads/sec^2
Give the torque equation that uses Rotational Inertia.
torque = rotational inertia*angular acceleration
An ornament is hanging from a mobile 20 cm to the right of the pivot. There is a second ornament hanging 40 cm to the left of the pivot. If the mobile is in rotational equilibrium, compare the masses.
The mass to the right has to be twice and much as the mass to the left.
How are angular acceleration and moment of inertia related?
inversely
Which one of Newton's Laws applies to an object that has rotational acceleration
N2L
A grinding stone starts with an angular velocity of ωi=4.0 rad/s and uniformly accelerates to a final angular velocity of ωf=16.0 rad/s over a period of 3.0 s. What is the angular displacement of the grinding stone?
30 rads