Density = Mass / Volume
Density of stone = 100 / 10 = 10 g/mL
If the density is higher than water, then the object will sink. If the density of the object is lower than water, then the object will float.
Since the density of the rock is 10g/mL and the density of the water is 1g/mL, the stone will sink.
The vector sum is the algebraic sum if the two vectors have the same direction.
The sum vector is zero if the two vectors have the same magnitude and opposite direction
Vector addition is a process that can be performed graphically using the parallelogram method, see attached, where the second vector is placed at the tip of the first and the vector sum goes from the origin of the first vector to the tip of the second.
There are two special cases where the vector sum can be reduced to the algebraic sum if the vectors are parallel
case 1. if the two vectors are parallel, the sum vector has the magnitude of the sum of the magnitudes of each vector
case 2. If the two vectors are antiparallel and the magnitude of the two vectors is the same, the sum gives zero.
In summary in the sum of vectors If the vectors are parallel it is reduced to the algebraic sum, also in the case of equal magnitude and opposite direction the sum is the null vector
Hmm well best i can do is: 7 km/h + 20 km/h = 27 km/h. should be your answer.
