A7-kg cube of copper (ccu = 386 j/kg-k) has a temperature of 750 k. it is dropped into a bucket containing 5.5 kg of water (cwater = 4186 j/kg-k) with an initial temperature of 293 k. let's try this again, but this time add just the minimum amount of water needed to lower the temperature of the copper to 373 k. in other words, we start with the cube of copper at 750 k and we only add enough water at 293 k so that it completely evaporates by the time the copper reaches 373 k. assume the resulting water vapor remaining at 373 k. how much water do we need ?

answer: the correct answer id option(d).

explanation:

snell's law refraction:

the angle of refraction =

the angle of incidence =

refractive index of air = = 1

refractive index of glycerol = 1.47

from the given options, the most closest answer to 63.72° is 65° of option (d).

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

conservation of mass

mass before something happens = mass afterwards