toki

is it when the angle gets 90 degree?

i cant get it.sorry.

i also tried much to get this angle

 

 

+1

 

 

 

Which affects what parameter in the formula for the period of a pendulum?

in the formula T=2pi*root of L/g

there is nothing to effect it with out L and g

but as far as i know pendulam works in free place.but there is water here

but you are right that the upward byuiant force affects the g.because if the bob gets a force F=mg in free place ,in water it will get a force F-f(upward force)

upward buoyant force

A simple pendulum sinks in water. The density of water is 1000kgm-3. The density of the bob is 1500kgm-3. The effective length of the pendulum is 1m. Gravitational acceleration is 9.8ms-2. What is the period of the pendulum? Neglect viscosity.

i can measure the period in the air or free place.but how can i measure the friction of water?

So what angle is that with respect to the vertical line? And what condition will maximize a shadow?

it is 7.125degree using trigonometry.

and it is in the opposite position .that is -7.125 degree

Yeah ,when the sheet will make 0 or 180 degree with the lamp light,there will be no shadow.

Yes

But how can I determine the maximum value using trigonometry?

Plz help me with any clue

i dont have ANY idea how to start it.

there is a lamppost which is 40 m high.5 m infront of the post there is a metal plate which is 8 m long.

which angle of the plate with the verticle line will give the longest shadow?

 

 

Which radius is the one that you want to use to convert rotational speed into linear speed? (I.e. what part of the wheel is touching the surface, so that a revolution can tell you the distance traveled?)

 

For the moment of inertia substitution, both radii will show up.

but if I want to find the moment of inertia I must have to use this two radios r1 and r2,isn't it?

if I do it,in the last solution I will find a ans with g,h,r1and r2.

because r1 and r2 cannot be cut up with the r^2 of w^2=v^2/r^2

for the height of the plane 'h'

mgh=0.5*I*w^2 +0.5*m*v^2

=.5*(.5*mr^2)*(v^2/r^2)+.5*mv^2

solving this give

v=root of (4/3 * gh)[for a cylinder ]

but for a ring there are tro Radios

inner and outer.so how I can solve it for a ring?

I mean that the ring is not thrown in any initial valocity.just as you have put the ring top of the plane and escaped it!

and this is for physics olympiad.not my homework!!

I have got the solution for a sphere or cylinder, in the physics by robert resnic.but cannt solve this problem for a ring.

yeah....

a ring of inner Radios r1 and outer Radios r2 is falling(free fall) from a plane, which is angled (theta) with the horizontal axis.

what will be itz final valocity?

(plz ans it using the moment of inertia for ring:(.5*m(r1^2+r2^2))

if I buy a motor from a shop I can just know itz power.

hpw I can know the angular valocity or the acceleration of it to determine the upward torque?

actually I'm from Bangladesh ♥

our curriculum does not cover calculas in high school level.

in college level we learn it.

and tnx all.

iv understood

but how Thin circular strip at distance r from center has area 2\pi rdr.

I don't know. I'm new high school student

according to nils bor it occurs because of spoky action.

for einstain itz just gloves!

for a dv volume cylinder we get dv=2*pi*r*dr*L

but why to multiply this r with dr.please make it understand