B. the reason we must wear seat belts
Momentum is conserved if and only if sum of all forces which are exserted on system equals zero. In our situation there are only internal forces, so by Newton's third law their vector sum is 0.
So
.
Kinetic energy of system at first:
. After:
. The secret is that other energy is in work of deformation forces (they in turn heat a bullet and a block).
Answer is A)
Velocity of an object is its rate of change of the object's position per interval of time. Velocity is a vector quantity which means that it consists of a magnitude and a direction. Magnitude is represented by the speed and the direction is represented by the angle. To determine the velocity components, we use trigonometric functions to determine the angle of the components. For the north component we, use the sine function while, for the west component, we use the cosine function. We calculate as follows:
north velocity component = (16.8 m/s) (sin 54°) = 16.4 m/s
<span>west velocity component = (16.8 m/s) (cos 54°) = 3.49 m/s</span>
Answer:d
Explanation:
Given systems are state of matter and do not contain any heat instead Heat is required to change Phase or raise the temperature of the particular system.
For example 600 kg of ice at 
Heat Required to convert it to water at
is

Where L=latent heat of Fusion 

