Work Done = Force x Distance Moved
Work Done = 25 x 15 = 375 Joules
Using V= vo +at with Vo = 0 and a= 4m/sec2.
V= 0+ 4x8= 32m/s
The rest energy of a particle is

where

is the rest mass of the particle and c is the speed of light.
The total energy of a relativistic particle is

where v is the speed of the particle.
We want the total energy of the particle to be twice its rest energy, so that

which means:


From which we find the ratio between the speed of the particle v and the speed of light c:

So, the particle should travel at 0.87c in order to have its total energy equal to twice its rest energy.
Answer:
B. They each contain the same amount of matter.
Explanation:
Scientifically, mass is the amount of matter in an object.
A. Whether an object is big or small does not mean that it will be a certain mass. If you have two objects that are the same size, the denser object will have more mass, and the less dense object will have less mass.
C. The amount of space an object takes up is called the volume.
D. Different combinations and amounts of elements can give you the same mass. Rocks, books and cans of soda are made of different things.