If Any object moves such that it covers an angle q at the fixed point (center of the circle) and its gap from the fixed point remains constant (radius of the circle)   Here R is constants  Now finding linear speed of

(i) hour hand (30 cm)

(ii) Minute hand (90 cm)

(iii) Second hand (60 cm)

Solution:- (i) time period of hour hand T = 12 hr = 12 x 3600 sec

v = r w (ii) Minute hand:- time period = T = 60 min = 60 x 60 sec (iii) Second hand:-

Time period= T = 60 sec

v = r w Types of circular motion: (on the basis of speed) (1) Uniform circular motion: (U C M)

Only direction of velocity is changing, magnitude remains unchanged. Now acceleration due to change in direction of velocity Using law of parallelogram    = 2v2 - 2v2 cosq

= 2v(1- cosq)   Now  sinq » q if  q <<<<  a = v w,   Direction of this acceleration is towards center (2) Non uniform circular motion (Non U C M) Here in this case direction as well as magnitude both are changing continuously therefore here two different named acceleration will be as,

(i) ac = aR (centripetal or radial acceleration)

(ii) at (Tangential acceleration)

Now,

Tangential acceleration.

Rate of change of magnitude of velocity”

v = R w   So at ^ ac Net acceleration for non-uniform circular motion.

Example:- A particle moving in a circular path of radius 2 meter and its velocity varies as  v = 10t2. Then net acceleration of the particle at t = 2 sec.

Solution: Given v = 10t2 = 20 x 2

= 40 m/s2  Centripetal force:- the force require to move in a circular path for any object with respect to inertial frame is called centripetal force. Note:- Centrifugal force will also have same magnitude but direction opposite to centripetal force.

Direction of this force is towards the center.

HORIZONTAL CIRCULAR MOTION (1) Only banking Here N sinq is C.P. provider But N cosq = mg  Safe speed

(2) Only friction

Here now m N is C.P. provider  N = mg   Safe speed

Friction and Banking both:- To prevent inward sliding

cosq + m N sinq = mg Divide   TO PREVENT OUTWARD SLIDING  N cosq - m N sinq = mg  v1 < Vsafe < v2 CONICAL PENDULUM T sinq = mrw2

T cosq = mg   Time period of conical pendulum    Join any of the batches using this book

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