<span>Recall formula for Kinetic energy is:
KE = 1/2mv^2, where KE = 275J
and momentum (which is 25.0 kg m/s) = m*v
Therefore substitute for KE and mv in the equation above to get speed
=> 275 = 0.5 * 25 * v
v = 275/12.5
v = 22m/s
to get mass m, recall momentum = m*v
=> 25= 22*m
m= 25/22 = 1.3663kg</span>
Answer: object B is negatively charged, object C is positively charged and object D is also positively charged
Explanation: since unlike charges attract and like charges repel, for object A which is positively charged and B to attract B must be negatively charged and then for B which is negatively charged and C to attract C must be positively charged and for C and D to repel they have to be of thesame charge which means D is positive as well.
d=vi*t+(1/2)gt²
d=11 m
g=9.8 m/s²
vi=0 m/s
11 m=0 m/s*t+(1/2)9.8 m/s²t²
11 m=4.9 m/s²t²
t²=11 m / 4.9 m/s²
t=√(11 m / 4.9 m/s²)=1.489... s≈1.5 s
Answer: the time the sone is in flight is 1.5 s