Question

6-If Earth stops rotating,then weight of an object on it will?
a-Increases
b-Decreases
c-Remains the same
d-Unpredictable

7-During unstable Equilbrium:
a-P.E increases
b-P.E decreases
c-P.E remains the same
d-Non of these

8-If a Body is Moving with non uniform angular velocity,then its troque will be?
a-Zero
b Maximum
c-Constant
d-Clockwise
15-Which of the following has same units?
a-Work and torque
b-force and stress
c-Both a and b
d-Non of these

Answer 1

thats not my homework . Its just a practice test
6 a ??? how ???
7 I think P.E remains same
8 dunno
15 A

Answer 2

i like to think of it in this way...if you are on a rotating planet, the gravitational force is used up for two things
a part of it to give you the required centripetal force, and the rest of it is used up to pull you down.. or the Normal force or in other words, the perceived weight

so as the planet rotates faster and faster and faster, more and more of the gravitational pull will be used up to provide you the centripetal force, and thus ur percieved weight decreases.. so obviously now you can think what happens if the planet stopped rotating all together

Answer 3

Whether it is stable or unstable, its equilibrium right?
and when objects are in equilibrium, there is no net force, hence no net change in their energies!

Answer 4

8th question is a little absurd if you asked me :P

Answer 5

oh wait.. its uniform angular velocity.. i read it as NON uniform..
ok can u think whats the answer?

Answer 6

@Mashy I got the first one .thanks for awesome explanation :)
but the second one is b in answer key . why ???

Answer 7

no its Ques 8 Non.uniform in ques @Mashy

Answer 8

for ques 8 Answer key saying A Zero I dunno how ??? :/

Answer 9

@Mashy

Answer 10

i think for question 8 is wrong here ans would be zero only in case when , we have uniform angular velocity because then angular acceleration will be zero and therefore by using torque formula \[\tau=r timesf=I\] we will have torrque = zero

Answer 11

and ans of 15 question is a

Answer 12

@amitsilswal thank you very much what you think about 7 IS P.E remains same ???

Answer 13

during unstable equilibrium P.E will increase . i can give u evidence for that

Answer 14

please Can you explain it ?

Answer 15

thats what in my answer key P.E would increases thanks again @amitsilswal

Answer 16

its my pleasure

Answer 17

So ques 8 is wrong right?

Answer 18

ya i thnik so

Answer 19

did u get my ans completely????????????

Answer 20

wb 15 ??? Answer key is again wrong here becuase showing C correct but I know that stress has not same unit as work .

Answer 21

ofcource forec has a unit N and stress has N/m squr

Answer 22

Oh noooo .not again . Answer key showing P.E decreases for 7 :(

Answer 23

but my ans is correct... because u can see it

Answer 24

but what you explain to me Is of higher level So its just ..... *-*

Answer 25

what standard do u belong/

Answer 26

12

Answer 27

ok m sorry i got it.. at the state of unstable equilibrium it has max energy ..but it decreases
with time and gets its lowest possible energy.. u can see it in the diagram .then if u have a ball at top and u disturb it ,,, it comes down therefore it is unstable. but if u disturb ball in the valley point it will have small oscillations(stable equilibrium) , and u know minimum energy corresponds to stability.. so the ryt ans is in case of unstable equilibrium P.E will decrease to become a stable equilibrium system

Answer 28

thank you so much @amitsilswal

Answer 29

did u get it now?

Answer 30

yeah I guess Im :)

Answer 31

gud

Answer 32

you are a awesome helper .Thanks again :D

Answer 33

oh thank... where are u from?