#1
mass of Sam = 75 kg
velocity of Sam = 18 m/s
now for momentum we can use
[tex]P = mv[/tex]
[tex]P = 75(18) [/tex]
[tex]P = 1350 kg m/s[/tex]
#2
Momentum of football = momentum of bullet
[tex]P_{ball} = P_{bullet}[/tex]
[tex]m_{ball}v_{ball} = m_{bullet}v_{bullet}[/tex]
[tex]0.25 v = 0.05 (500)[/tex]
[tex]v = 100 m/s[/tex]
#3
As per Newton's law we know that net force is given as
[tex]F = \frac{\Delta P}{\Delta t}[/tex]
now we have
[tex]\Delta P = m(v_f - v_i)[/tex]
[tex]\Delta P = 55(20 - 0) = 1100 kg m/s[/tex]
also we know that
[tex]\Delta t = 0.5 s[/tex]
form above equation we have
[tex]F = \frac{1100}{0.5} = 2200 N[/tex]
#4
As per Newton's law we know that net force is given as
[tex]F = \frac{\Delta P}{\Delta t}[/tex]
now we have
[tex]\Delta P = m(v_f - v_i)[/tex]
[tex]\Delta P = 0.16(44 - (-38)) = 13.12 kg m/s[/tex]
also we know that
[tex]\Delta t = 0.002 s[/tex]
form above equation we have
[tex]F = \frac{13.12}{0.002} = 6560 N[/tex]
