The weight of the needle is 0.007 N.
Explanation:
Surface tension is the force acting on the surface of any fluid or film due to the attractive forces on the surface of them. So it is measured as force acting per unit effective length on the surface. The effective length is the distance or the length which is in contact with the surface.
For example, in the present case, the needle can be in contact with the water body from both sides of the needle. So effective length of the needle will be 2 times the length of the needle. Then the surface tension on the water due to the needle will be
As the length of the needle is given as 5 cm = 0.05 m and the surface tension of water is given as 0.07 N/m, then the weight of the needle will be equal to the force applied by the needle.
So, the weight of the needle is 0.007 N.
Answer:
Absorption, in wave motion, the transfer of the energy of a wave to matter as the wave passes through it. The energy of an acoustic, electromagnetic, or other wave is proportional to the square of its amplitude—i.e., the maximum displacement or movement of a point on the wave; and, as the wave passes through a substance, its amplitude steadily decreases.
Explanation:
Answer:
The girl will move with constant velocity
Explanation:
If after a certain time t_0 the velocity of the girl is v_0 =gt_0 and the upward force on the girl due to rope is mg ,where g is gravitational acceleration. Then the girl will move down with the constant velocity v_0 .
The girl will move with constant velocity,as explained above.