Answer:
No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings.
Explanation:
Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart such that, in the liquid, the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature. Similarly, energy is needed to vaporize a liquid, because molecules in a liquid interact with each other via attractive forces. There is no temperature change until a phase change is complete. The temperature of a cup of soda initially at 0ºC stays at 0ºC until all the ice has melted. Conversely, energy is released during freezing and condensation, usually in the form of thermal energy. Work is done by cohesive forces when molecules are brought together. The corresponding energy must be given off (dissipated) to allow them to stay together Figure 2.
The energy involved in a phase change depends on two major factors: the number and strength of bonds or force pairs. The number of bonds is proportional to the number of molecules and thus to the mass of the sample. The strength of forces depends on the type of molecules. The heat Q required to change the phase of a sample of mass m is given by
Q = mLf (melting/freezing,
Q = mLv (vaporization/condensation),
where the latent heat of fusion, Lf, and latent heat of vaporization, Lv, are material constants that are determined experimentally.
Running on sand requires 1.6 times more energy spent than running on hard surface, so the force applied by our foot on sand is less.
Answer:
Explanation:
The relationship between angle and wavelength for maxima and minima in Young's double slit experiment is given by
For constructive interference
For Destructive interference
where 
m=order of maxima and minima
for second order maxima i.e. 
For smallest separation taking 
Answer:
Radians
Explanation:
The angular speed is a measure of the rotation speed of a body. It is defined as the angle rotated by a unit of time. Thus, It refers to the angular displacement per unit time and is designated by the Greek letter 
. Its unit in the International System is radian per second (rad / s).
Do you remember this formula for the distance traveled while accelerated ?
<u>Distance = (initial speed) x (t) plus (1/2) x (acceleration) x (t²)</u>
I think this is exactly what we need for this problem.
initial speed = 20 m/s down
acceleration = 9.81 m/s² down
t = 3.0 seconds
Distance down = (20) x (3) plus (1/2) x (9.81) x (3)²
Distance = (60) plus (4.905) x (9)
Distance = (60) plus (44.145) = 104.145 meters
Choice <em>D)</em> is the closest one.
