Answer:
(100,84.67,89.33) m/s
Explanation:
From Newton's second law,
Impulse = Final momentum- initial momentum.
I = Mf-Mi.............. Equation 1
make Mi the subject of the equation
Mi = Mf-I............ Equation 2
Where I = Impulse. Mf = final momentum, Mi = initial momentum.
But
I = Ft.................... Equation 3
Where F = Force, T = time
Given: F = (21,-11,44) N, t = 4 s.
I = 4(21,-11,44)
I = (84,-44,176) N.s
Also,
Mf = mVf................ Equation 4
Where m = mass, Vf = Final velocity
Given: m = 12 g, Vf = (107,81,104) m/s.
Substitute into equation 4
Mf = 12(107,81,104)
Mf = (1284,972,1248) kgm/s.
Substitute the value of I and Mf into equation 2
Mi = (1284,972,1248)-(84,-44,176)
Mi = (1200,1016,1072) kgm/s
Also,
Mi = mVi
Where Vi = Initial velocity.
make Vi The subject of the equation
Vi = Mi/m.......................... Equation 5
Given: m = 12 kg, Mi = (1200,1016,1072) kgm/s
Substitute into equation 5
Vi = (1200,1016,1072)/12
Vi = (100,84.67,89.33) m/s
