Answer:
F=12.5N
Explanation:
Net force = rate of change of momentum
[tex]F = m*a[/tex]
so find the change of momentum P
Pdown
[tex]P=m*v_1=0.42kg*3m/s[/tex]
Pup
[tex]P=m*v_1=0.42kg*6.5m/s[/tex]
dP = change in P
[tex]dP= 0.42kg (3- -.6.5)m/s =3.99 kg m/s[/tex]
[tex]dT = 0.32 s[/tex]
so
[tex]F = \frac{dP}{dt}=\frac{3.99Kg*m/s}{0.32s} =12.468 N[/tex]