Term

Definition
when an object spins on its axis in rotational motion 


Term
What is angular displacement? What is its symbol? What units is it measured in? 

Definition
the change in the angle as an object rotates; theta; revolutions, degrees, radians 


Term
What is the angular displacement of a second hand on a clock in ten minutes? 

Definition
10 revolutions; 2 pi; 3600 degrees 


Term
What is angular velocity? What is the symbol? What units is it measured in? 

Definition
the rate of rotation (rev/sec); omega; change in angular displacemnt/change in time; rev/sec or rad/sec or degrees/sec 


Term
What is the angular velocity in radians of a tops that turns 100 times in 5 seconds? 

Definition


Term
What is tangential speed? How does the tangential speed vary across a rotating disk? How do you convert from angular velocity to tangential velocity? 

Definition
the actual meters/sec it is traveling; as you move outward, the faster you go; V=r(omega) and omega must be in radians 


Term
An object has an angular velocity of 50 radians/sec. At a distance of .5m from the axis of rotation what is the tangential speed? 

Definition


Term
What is angular acceleration? What is the symbol? What are the units? 

Definition
the rate of change of angular velocity; aplpha=change in angular velocity/change in time; rev/s squared 


Term

Definition


Term
An object spinning at 1000 rpm slows to a stop in 10 seconds, what is the angular acceleration? 

Definition


Term
What causes rotation? What is torque? 

Definition
torque; rotational effect caused by parallel forces 


Term
How do you calculate torque? 

Definition


Term

Definition
perpendicular length from the pivot point to the force 


Term
What happens to the gorque if the line of the force passes through the pivot point? 

Definition


Term
How do you calculate torque if the force is an angle to the object? 

Definition


Term
What is rotational inertia or the moment of inertia? 

Definition
when an object starts rotating, it wants to keep rotating; rotational inertia = moment of inertia 


Term
What deteremines how much rotational inertia something has? 

Definition
the distribution of the mass; the big wheel has more rotational inertia than a small wheel 


Term
What is the center of gravity (mass)? 

Definition
the point at which you draw your force vector down; where the force of gravity acts 


Term
when will toppling occur? 

Definition
when the center of gravity is not over the base of support 


Term
What are the 3 types of equlibrium? 

Definition
stable, unstable, equilibrium 


Term
What are the two conditions of equlibrium? 

Definition
translational and rotational; translationalFup=Fdown; rotationalCW torque=CCW torque; both of these conditions must be met in order to be in equlibrium 


Term
review all problems: seesaw, torque, equlibriant, bridge, angular displacement, velocity, acceleration, etc 

Definition


Term
What is the angular displacement of a second hand in 1.5 minutes? 

Definition
1.5 revolutions; 540 degrees; 3 pi radians 


Term
What is the angular displacement of a second hand in five minutes? 

Definition
5 revolutions, 1800 degrees; 10 pi radians 


Term
Which part of the earth's surface has the greatest rotational speed about the earth's axis? 

Definition


Term
Which part of the earth's surface has the greatest linear speed relative to the axis? 

Definition


Term
On a particular merry g round, the horses along the outer rail are located three times farther from the axis of rotation than the horses along the inner rail. If a boy sitting on a horse near the inner rail has a rotation speed of 4 rpm and a tangential pseed of 2 m/s, what will be the rotational speed and tangential speed of his sister who is sitting on a horse along the outer rail? 

Definition
4 rpmrotational; 6 m/slinear 


Term
A wirte with 4 light bulbs is twirled ina circle. The bulbs are numbered 14, with four being on the outside of the circle and 1 being towards the center. Which of the bulbs have the greatest rotational speed? Which of the bulbs has the greatest tangential speed? 

Definition
they have the same rotational speed; bulb 4 has the greatest tangential speed 


Term
A fan rotating at 200 rpms takes 15 seconds to stop turning when it is turned off, what is the angular acceleration? 

Definition
0200/15=13.3 rev/min/sec 


Term

Definition


Term
What are the charateristics of torque? 

Definition
different from force, causes rotation, produced when a force is applied parallel to another force, measured in meter newtons 


Term

Definition


Term

Definition
perpendicular distance from F to pivot point 


Term
What when force is applied further from pivot point? 

Definition


Term
How do you calculate the torque if the force is at an angle? 

Definition
find the y component and multiply by the l 


Term
the more mass, the more____. 

Definition


Term
What are the characteristics of rotational inertia? 

Definition
varies with the radius and distribution of mass; as the radius increases so does the intertia; as the distribution is further ot the inertia increases 


Term
Why does a tight rope walker carry a long pole? 

Definition
it gives him a vetter moement of inertia so he doesnt fall 


Term
Why do we bend our knees more when we run? 

Definition
it reduces our moment of inertia 


Term
Where is the center of gravity of a bicycle tire located? 

Definition


Term
What is unstable equilibrium? 

Definition
the center of gravity goes lower and is easy to turn over 


Term
What is stable equlibrium? 

Definition
the center of gravity must go up; hard to turn over 


Term
What is neutral equlibrium? 

Definition
center of gravity stays in the same place (ball) 


Term
When you balance an object, are you balancing weight or torque? 

Definition

