im trying to do these homework problems but really don't know where to begin. they deal with multiple systems and they seem really easy i just don't know the formula to apply. any help with these would be appreciated. ========================================================= 1) A 1000 kg car pushes a 2000 kg truck that has a dead battery. When the driver steps on the accelerator, the drive wheels of the car push against the ground with a force of 4500 N. What is the magnitude of the force of the car on the truck? ========================================================= 2) The 1.0 kg block in the figure is tied to the wall with a rope. It sits on top of the 2.0 kg block. The lower block is pulled to the right with a tension force of 20 N. The coefficient of kinetic friction at both the lower and upper surfaces of the 2.0 kg block is 0.440 (static friction). What is the tension in the rope holding the 1.0 kg block to the wall? What is the acceleration of the 2.0 kg block? http://s93755476.onlinehome.us/stuff/knight.Figure.08.27.jpg ========================================================= 3) The 100 kg block in figure takes 5.50 to reach the floor after being released from rest.What is the mass of the block on the left? http://s93755476.onlinehome.us/stuff/knight.Figure.08.33.jpg ========================================================= 4) A 10-m-long glider with a mass of 680 kg (including the passengers) is gliding horizontally through the air at 30 m/s when a 60 kg skydiver drops out by releasing his grip on the glider. What is the glider's speed just after the skydiver lets go?