why does a spring strecthes when weight is put on?
454576
Because the weight applies a force to the spring.  F=-kx, so x = -F/k.  The great the force, the greater the stretch.  This is because many metals have memory and try to restore themselves to previous states.  If you bend it, the metal will try to bend back to where it was.
646742
Muscle is heavier than fat.
200535
Assuming their is no frictional drag between the table and the block, the only interaction here is between the block (a mass), and the spring, and neither knows nor cares whether they are on Earth, on Mars, or in middle space. The block is a mass to be moved by the restorative force of the stretched or compressed spring, and the spring's restoration force does not depend on where it is, nor does the mass of the block change with location. So the period of motion will remain the same. If this were a problem of vertical motion where the block was being lifted against the force of gravity, then the problem would be different.
57335
is due to the movement of a body , when a body is acelerating because it's spinning or something , it causes a drag force that affects the objects on that body ; it's not a ¨real force¨ (like gravity or a spring for example)cause is due to an acceleration; and because Newton's laws are applied only in inertial frames , people came out with this ¨ficticious forces¨( like this one and the centrifugal force for example) so we can be able to apply F=ma also in non inertial frames
48086
Sometimes, you weigh less, gravity's pull does not change, doy!
658774
I would think you would use the force created by compressing the spring.\n\nThis force is given by the equation:\n\nF = k(Li - Lc)\n\nWhere:\nF = force\nk = spring constant\nLi = uncompressed spring length\nLc = compressed spring length\n\nThe below link is for a calculator for this force.\n\nhttp://www.efunda.com/DesignStandards/springs/calc_comp_Fstress.cfm
641452
opposite force being applied
98858
sounds like you need to stretch more, you are pulling ligaments inside of your nana, it's not bad, but if you strecth alot, and it still doesn't help, you could be pulling the ligaments/tendons from their connection points on the pelvis
682825
how does it bounce without springs?
166750
Like a stretched spring.  Refer link for image.
604408
You are either doing something incorrectly and straining your back or you are using muscles that are not used to being used, in that case you will eventually break them in.
454463
There are many answers to your question. Gravity obviously. Another example is if you are try to lift a car with a lever or using a pulley to lift something.
378368
Lets take a mattress, for example.\n\nThe more coils, the less spring rate.  More coils means there is more support because there is a heavier gauge wire used in the coils.  The coils take up more "air space".  This doesn't leave much room for bounce/spring.\n\nLess (number of) coils means there is more air space between the coils, and there is more room for the coils to bounce and move around.  :-)
641340
it would double. imagine you stretch a spring with constant k a distance x using force f=kx. now while you are holding the end at displacement x, also hold the middle of the spring, which has been displaced x/2. now cut the spring in the middle while holding it, so the second half falls off and the first half is still stretched. since the first half is not stretched any farther than it was before, the force is the same. the displacement, however is x/2. so, the new spring constant is 2k.\n\nspring constant is really a misnomer; its not constant for the material, but only for that spring of that length. it should really be given as a constant independent of the length of the spring, constant per unit length, but alas it is not.
738949
the intercepe on the h axis will give 1/mass of the spring.\nSince, T is directly proportional to m, so if T decreases, this means m decreases, and hence the height of the mass loaded on the spring, from the ground increases.\nWhen T=0, then, the loaded mass must be zero. Hence, the h intercept gives the mass of the spring only.
789370
Probably compensation for an unnatural move...it doesn't feel right, so your body tries to compensate for it.
574012
I've alread answered two of your questiions in my last answer....\n\nIn this one, the guys above are correct - however, I'd try working it out for myself if I was you. Your tutor will soon realise something is wrong if you are giving answers to a subject you don't understand. Read the chapter, ask you teacher if you need more help. Learn Newtonian mechanics for yourself.