Answer:
a) 1.67 m/s
b) 23kJ
Explanation:
We need to apply the linear momentum conservation formula, that states:

in this case:

the initital kinetic energy is:

and the final:

The energy lost is given by:

Answer:
hm my mom said the net force changes
Answer: 3 seconds
Explanation:
Initial velocity(u) of projectile A in vertical direction = 0m/s
acceleration due to gravity a=g=9.81m/s^2
Time taken(t) of projectile A = 3s
Initial velocity of projectile B = 0m/s(vertical direction)
We can get height of cliff using parameters of projectile A since it's the same location.
Height(S) = u×t + 0.5×a×t^2
u =0
S= 0.5×9.81×3^2 = 44.145m
Time taken for projectile B to reach the ground:
S = u×t + 0.5×a×t^2
u =0, S=44.145m, a=9.81m/s^2
44.145 = 0.5×9.81×t^2
44.145 = 4.905×t^2
44.145 ÷ 4.905 = t^2
9 = t^2
t = sqrt(9)
t = 3seconds