Question

Rotation Homework 1 

.1.) Clearly explain the difference between rotation and a revolution. 

2.) What is linear speed called when something is rotating? 

3.) At a constant radius, how does the tangential speed change as the angular velocity increases? 

4.) At a constant angular velocity, how does tangential speed change as the radius increases? 

5.) A ladybug sits halfway between the axis and the edge of a rotating disk. What will happen to the ladybug's tangential velocity if 

 a.) The RPM rate is doubled? 

 b.) The ladybug moves to the edge? 

 c.) Both a and b happen at the same time? 

6.) A taxi driver wishes to increase his profits by changing out his tires to a different size, from the above ideas, should he use larger or smaller tires?

7.) Mars is about twice as far from the sun as Venus is. A Martian year, which is the time it takes to go around the sun, is about three times as long as a year on Venus.

a.) Which of these 2 planets has the greater angular velocity?

b.) Which planet has the greater tangential velocity?

Answer 1

1)

rotation: when an object moves around a circular path in an internal axis is called rotation. the axis of rotation is imaginary.for example Earth or moon rotates around itself.

revolution: when an object circle around an external imaginary axis that is called the revolution. for example, planets revolve around Sun

2)

when something is rotating the linear speed is called as tangential speed. because the direction of the speed in a circular path is making tangent to that point.

3)

v= tangential speed

r= radius

w= angular speed.

if angular speed increases then the magnitude of tangential speed also increases as both are directly proportional.

4)

if radius increases keeping angular speed constant then the magnitude of tangential speed also increases as both are directly proportional.

5)

a)

if RPM is double that means angular speed is double

so tangential speed is also

b) ladybug moves to the edge means

so the tangential speed is also doubled.

c) if both happens the same time

so tangential speed increases to 4 times

6)

in both cases, the tangential speed remains same because for smaller tire the angular speed is more but the radius is same and in larger tire radius is more but angular speed is less. so the change the tire can not support him to increases its speed.

7)