8) A hanging 7.5 kg object stretches a spring 1.1 m. What is the spring constant? Show your work. 9) A spring has a constant of 875 N/m. What hanging mass will cause this spring to stretch 4.5 m? Show your work.

Un jugador de beisbol batea un foul recto en el aire.la pelota deja el bate con una rapidez de 120 km/h. en ausencia de resistencia del aire. ? cual sera la rapidez de la pelota cuando la atrape el catcher

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)

Acar is traveling 35 mph on a smooth surface . if a balanced force is applied to the car what happens?