I have a physics test in a week and am having trouble coming up with the proper equations to solve the problems. Does any body want to offer hint or guidelines to solving these? I have been working on these but I dont think I am approaching the questions appropriately. 1) A 920-kg sports car collides into the rear of a 2300-kg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.8 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires and road is 0.80, calculates the speed of the sports car at impact. What was that speed? 2) A toy car (m = 100 g) is launched horizontally along a track by a spring loaded mechanism (k1 = 1000 N/m). The mechanism is “armed” by compressing the spring by and then placing the car in front of it. After being launched, the car rolls down an inclined ramp until it reaches another level section 0.6 meters below the first. On this section of track it encounters another spring (k2 = 2000 N/m). The car compresses this second spring by 6 cm before momentarily coming to rest. Assume the whole system is frictionless. a) How much was the launching spring compressed by before firing? b) If the car had instead been launched up an inclined section of track, to what height would it have reached before coming back down? 3) A 1500-kg car traveling at 90.0 km/h east collides with a 3000-kg car traveling at 60.0 km/h south. The two cars stick together after the collision. What is the velocity (speed and direction) of the cars just after the collision (before friction has had time to act)? 4)A certain rope swing is 4 meters long and will break if it has to support more than 1666 N of force. What is the maximum height that an 85 kg person should launch themselves from so that the rope doesn’t break as they swing on it? (Hint: The most force will be applied to the rope when the swinger is at the bottom of their swing). 5)Given that the acceleration of gravity at the surface of Mars is 0.38 of what it is on Earth, and that Mars’ radius is 3400 km, determine the mass of Mars.