IIT JEE , AIEEE Forum - Physics , Mechanics

ashish_banga

When a particle moves in a circle with a uniform speed -

1. its velocity and acceleration are both constant

2. its velocity is constant but the acceleration changes

3. its acceleration is constant but the velocity changes

4. its velocity and acceleration both change

arpan1

well it should b 4

because both change in directions

joyfrancis

(3) since there is no tangential acceleration and the magnitude of radial acc is const...the velocity however changes, due to change in direction

dream

The answer should be 4

the magnitude of both velocity and acceleration remains constant but their direction changes continuously

riku

circular motion is described of atleast one acceleration,, for a point which is directed towards centre..

From inertial frame ,, its the direction is not fixed,, and also the direction of velocity,, which is tangential ,, is also not constant...

If anyhow,, the frame of rotation becomes inertial(practically not possible),, then both will be constant with direction..Both go together..(not talking of net acceleration and velocity in this case)..

shub

it should be (3)......
velocity will constantly change it's direction......therefore it is not constant......
but for acceleration....there is no tangential acceleration due to constant speed....the acceleration is constant in magnitude directed always towards the centre.....

rachit12

yes tha answer is 3 !!
isn't it dce question???

arpan1

well to all those who think the ans is c

how is the direction of accn. fixed and btw center is not a direction , its a point only

and by definition a point has no direction

try visualising the accn vector with the motion of particle

rate me

riku

boss acc. cant be said to be having fixed direction,,, the point of directing is fixed,, but direction changes because the particle changes its position... We can consider it vector, if we take it to be a free vector,, but in physics we deal with dependent vectors dear(in most cases), but for calculative purposes free vectors!!

isomniac

ans shud be 3

bcoz acc is constant as only centipetal force is providing acc

thr is no tangential acc

velocity changes due change in dir as it is a vector

ganesha1991

hey guys
its right of u people who r saying
centripetal acceleration is the only acceleration present
but it also changes direction as the body starts moving

so both acceleration and velocity change
so it is 4

unni_enter

yup the ans is 4) as the centripetal acc. is always directed towards the center and hence changes its direct with the particle and so is the case with velo(tangential) but both const magnitudes

ashish_banga

answer is 4

saurabh92

yep...

itz 4...

dream

those who think the answer is 3

see guys arpan has explaines it nicely

i wud try to explain in my own ways

when u consider the acc, true that it is directed towards the centre, but the direction of centre of circle changes from different points on circumference

and well if u say that direction is constant , u say that co ordibnate system constantly changes

but thats not true

the best method to realize it is to visualize it all

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