Answer:
γ = 1.42 * F1 * r1 - 6.52 Nm
Explanation:
The first kid will apply a torque of:
T = F * d * sin(a)
T1 = F1 * r1 * sin(80)
T1 = 0.98 * F1 * r1
The second kid applies a torque of
T2 = -15 * 0.3 * sin(90) = -4.5 Nm (negative because it is in the opposite direction as the other kid)
The angular momentum of the door is:
I = 1/3 * m * L^2
I = 1/3 * 13 * 0.4^2 = 0.69 kg*m^2
The total torque applied is:
T = T1 + T2
T = 0.98 * F1 * r1 - 4.5 Nm
The angular acceleration will be:
γ = T / I
γ = (0.98 * F1 * r1 - 4.5) / 0.69
γ = 1.42 * F1 * r1 - 6.52 Nm
