Rotation
Motion about an internal axis
Rotary motion
The product of force and radius
Torque
The gravitational potential energy of a flower pot weighing 2 kg and sitting on a window sill that is 9 m above the ground
About 180 J
Matter is anything having
The man who wrote Principia
Isaac Newton
The time rate of change of angular displacement
Angular velocity
In the law of torque, what quantity is comparable to mass in Newton’s second law?
I, rotational inertia
The type of collision in which kinetic energy is conserved
Elastic
The term ____ is often defined as "the capacity to do work."
Strong force
If a disk and a ring of the same mass and radius are released at the same time at the top of an inclined plane, the ____ will roll to the bottom first.
disk
Define the condition for rotational equilibrium for a body
Sum of cw torques = sum of ccw torques
The momentum of a 3 kg object moving at 10 m/s
30 kg m/s
The statement “If a system is isolated from non-conservative forces, then the total mechanical energy must remain constant” is the law of ________________
Conservation of mechanical energy
Friction has direction _________ to motion
Opposite
The time it would take for a ball rolling at 4π rad/s to rotate one time is _____
0.5 s
The amount of torque exerted on a lug if 30 N is applied perpendicular to the end of a 0.4 m wrench
12 Nm
When objects stick together, it is a ______ collision
Completely inelastic
A skater, arms out, with rotational inertia of 6 kgm2 spins at a rate of 6 rad/s. If she pulls in her arms she reduces her rotational inertia to 2 kgm2. She will now spin at a rate of
18 rad/s
This is the ratio of mass to volume of an object
Density
When you turn on the fan, it accelerates from zero to 20 rad/s in 4 s. What is the angular acceleration?
5 rad/s2
If a torque of 60 Nm is applied to an object with rotational inertia of 12 kgm2, the resulting angular acceleration is
5 rad/s2
If a 6 kg ball collides with a 2 kg pin, and the velocity of the ball before collision is 3 m/s, and after collision it is 2 m/s then the pin (which was at rest initially) is moving at ______ after the collision
3 m/s
A 1 m beam which can rotate about a pivot point in the middle has the following perpendicular forces applied to it: 12 N at the left end, 5N at a distance 0.2 m to the right of the pivot point, and 10 N on the right end. All forces are directed upward. Is the beam in rotational equilibrium?
Yes
A rifle fires a 0.002 kg bullet into a block of balsa wood. The average force exerated on the bullet by the wood, if it’s decelerated at a rate of 30000 m/s2 is?
(.002)(30000)= 60 N