They are both in motion because an object is not at rest, but moving so slow it could be at rest. A car going at the same constant velocity is neither speeding up or slowing down, an object "at rest" is also moving at a constant rate, not speeding up or slowing done.
Answer:
20 kg
Explanation:
remember the equation f=ma.
100 N=force
5 m/s2= acceleration
so you need to divide force by acceleration: 100 N/ 5 m/s2= 20 kg, to get the mass.
To calculate the mass of the fuel, we use the formula

Here, m is the mass of fuel, V is the volume of the fuel and its value is
and
is the density and its value of 0.821 g/mL.
Substituting these values in above relation, we get
Thus, the mass of the fuel 247 .94 kg.