Answer:
Net Force = 0
Explanation:
Causes objects to accelerate. Balanced Forces. Two equal forces push in opposite direction causing no change in motion causing net force = 0.
Answer: 39.2 m/s
Explanation:
You can use the kinematic equation:

We know the final velocity because it says it came to a stop. So now all we gotta do is plug in.

Answer:
1.5m
Explanation:
Speed of waves is given as the product of the wavelength and frequency. Sometimes when frequency is not given but the period is given, we get the frequency as the reciprocal of the period. The speed of waves is given in m/s, wavelength in m while frequency in Hz.
Speed, s= fw and making w the subject of formula,

Substituting 300, 000, 000 m/s for s and 200, 000, 000 for f then we obtain that

F=ma=m(change in velocity/change in time)
Number 1
F=ma
F=55kg(1.1ms^-1/1.6s)=37.8N
Number 2
F=ma
F=0.440kg(10ms^-1/0.02s)=220N
Number 3
F=ma
F=1400kg(15ms^-1/0.73s)=2.88*10^3N or 28,767N
Any questions please feel free to ask.