@ sakshi 
yes, i do agree that system of particles and rotational motion is a complicated chapter , beacuse that involves many graphs are equation , formula which u have to remember . 
and donot follow ncert for mechanics , 
for that chapter , frst start with h c verma/ university physics ( anyone that u have) 
then after reading the theory from their , u can go ahead with the questions given in hc verma , (speially objective ) 
after that , take UNDERSTANDING PHYSICS by d c pandey ( mechanics part )and solve the ques , it will give u how the aiims and neet is going to ask the questions . 
at first u will noit able to solve h cverma ques , bt donot loose hope beacuse hcv is not fully required for medical entrances . 
MAIN FOCUS – INERTIA OF A PARTICLE , AND RIGID BODY CONFIGURATION . 
u can also take last 28 years papers of aiims and neet , of arihant and mtg , otherwise its avaliable on askiitian site also . 
ALL THE BEST . 
 
						

							
PLEASE MAKE A VISIT ON:
http://www.askiitians.com/iit-jee-physics/mechanics/
http://www.askiitians.com/revision-notes/physics/circular-and-rotational-motion/
THANKS