Given :
Mass of object, m = 1.5 kg.
To Find :
The momentum of boulder dropped from a cliff after 3 seconds.
Solution :
Speed of boulder after 3 seconds of free fall is given by :
v = u + gt ( Equation of motion )
v = 0 + 10×3 ( g = acceleration due to gravity )
v = 30 m/s
Now, momentum is given by :
P = m × v
P = 1.5 kg × 30 m/s
P = 45 kg m/s
Therefore, momentum of boulder is 45 kg m/s.