Use the equation of gravitational force, that is, use F=-G (m1)(m2)/r^2, to find the weight of a crate whose mass is 30 kg. The Earth’s mass is 6x 10^24 kg, and its radius is 6.4x 10^6 m. ( G =-6.67x10^-11)

Ahot-air balloon takes off from the ground traveling vertically with a constant upward acceleration of magnitude g/4. after time interval δt, a crew member releases a ballast sandbag from the basket attached to the balloon. how many seconds does it take the sandbag to reach the ground? (express your answer in terms of δt)