Explanation:
The question says that "Does a 60 kg person running at 4 m/s have more kinetic energy than a 10 gram projectile at 300 m/s ?
"
Speed of a person is 4 m/s
Mass of a person is 60 kg
Kinetic energy of a person is : 
So,

Mass of a projectile is 10 grams or 0.01 kg
Speed of a projectile is 300 m/s
Kinetic energy of a projectile is :


So, it is clear that the kinetic energy of a person is more than that of the kinetic energy of a projectile.
Acceleration is the
rate of change of velocity, a body moving with uniform velocity does not
possess acceleration at all i.e. acceleration is zero
Explanation:
It is given that net gravitational force on M is exactly equal to zero. Hence, distance to M from the bigger mass is 3m. Therefore, expression for net force will be as follows.
So,

The first term is negative as the third mass is located between the other two masses. This means that 3 m will be pulling it leftwards (negative x direction) and m will be pulling it rightwards (positive x direction).

On dividing both sides of the equation by G.m.M, we get the following.


0 = 
Using the formula,
the value of x comes out to be equal to +2.37 (not usabale) and -0.634 (usable).
Hence, we can conclude that the third mass will be located 0.634 meters away from the 3 m mass.
It will act upon a buoyant force on the magnitude of which is equal to weight of the fluid