Assuming north as positive direction, the initial and final velocities of the ball are:

(with negative sign since it is due south)

the time taken is

, so the average acceleration of the ball is given by

And the positive sign tells us the direction of the acceleration is north.
Mass = 1.2 kg = 1200 grams.
Volume = mass/density = 1200 cm3.
Hope this helps!
Answer:
2.0 m/s/s
Explanation:
The acceleration of an object is the rate of change of velocity of the object.
Mathematically, it is given by:

where
u is the initial velocity
v is the final velocity
t is the time taken for the velocity to change from u to v
Acceleration is a vector, so it has both a magnitude and a direction.
For the runner in this problem, we have:
u = 0 is the initial velocity (he starts from rest)
v = 8.0 m/s is the final velocity
t = 4.0 s is the time taken
Substituting, we find

Answer:
7800kg/m³
Explanation:
Density of iron in CGS unit is 7.8 g/cm3. Its density is SI is
Given the density of iron = 7.8 g/cm3.
The SI units must be in kg/m³
7.8g = 7.8/1000 kg
7.8g = 0.0078kg
1cm³ = 0.000001m³
7.8g/cm³
= 0.0078/0.000001 kg/m³
= 7800kg/m³
Hence the density in SI unit is 7800kg/m³