A substance has a melting point of 20°C and a heat of fusion of 3.9 x 104 J/kg. The boiling point is 150°C and the heat of vaporization is 7.8 × (10) with superscript (4) J/kg at a pressure of 1.0 atm. The specific heats for the solid, liquid, and gaseous phases are 600 J/(kg∙K), 1000 J/(kg∙K), and 400 J/(kg∙K), respectively. The quantity of heat required to raise the temperature of 3.80 kg of the substance from -6°C to 128°C, at a pressure of 1.0 atm, is closest to
A. 560 kJ.
B. 770 kJ.
C. 620 kJ.
D. 210 kJ.
E. 470 kJ.
convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.
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.