2. Refer to the diagram below. A spring-loaded launcher is aimed vertically upward, and compressed 0.13 m beyond its equilibrium position, then locked into place. The spring constant is k = 60000 N/m. A block of mass 2 kg is placed on the launcher. When the spring lock is released, the block is launched upward to a maximum height, H. What is this height, H, if the block loses 17 Joules of mechanical energy to air resistance (during its upward flight)? Show all calculations.

A 1.000 ´ 103 kg car is moving at 90.0 km/h (25.0 m/s) as it exits a freeway. The driver brakes to meet the speed limit of 36.0 km/h (10.0 m/s). Was work done by the car brakes and other friction forces in the process? How much? __________________________________________________________ __________________________________________________________

A 3.12-kg particle is subject to a net force that varies with position as shown in the figure. The particle starts from rest at x = 0. Fx (N) 3 2 1 x (m) 0 2 468 10 12 14 16 What is its speed at the following positions? (a) x = 5.00 m m/s (b) x = 10.0 m m/s (c) x = 15.0 m m/s

Rough Patch: A 0.41 kg mass is placed next to a spring as shown in the figure. The spring is compressed by 0.10 m and released, launching the mass horizontally. The mass slides across a rough patch of length 0.57 m where the coefficient of kinetic friction is 0.257. (You can ignore friction everywhere else.) It then slides up a smooth ramp of length 2.45 m that raises it to a final height of 0.20 m, after which it slides along horizontally. Its final speed is 2.04 m/s. What is the spring constant of the spring? k h M

a 16 kg girl slides down a playground slide that is 4.8 m high. when she reaches the bottom of the slide, her speed is 1.9 m/s. the acceleration of gravity is 9.81 m/s^2. how much energy was dissipated by friction? answer in units of J. If the slide is inclined at 40 degrees what is the coefficient of friction between the girl and the slide?

2. A person pushes a 2500 kg car from rest to a speed of v, doing 5000 J of work in the process. If the car moves a distance of 25.0 m during the time that the mechanic is pushing and resistive force are ignored, find (a) the car's final speed and (b) the horizontal force exerted on the car. Answers: (a) 2.00 m/s, (b) 200 N

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A 2.0 kg object travels along the x-axis. A single conservative force acts on the object. The potential energy U associated with the force is shown in the graph as a function of x. The particle is at rest at x = 0.0 m. What is the speed of the particle at x = 9.0 m? (Enter your answer in units of m/s. Only enter the number using 2 significant figures.)

A fully loaded, slow-moving freight elevator has a cab with a total mass of 1500 kg, which is required to travel upward 60 m in 3.5 min, starting and ending at rest. The elevator's counterweight has a mass of only 930 kg, so the elevator motor must help pull the cab upward. What average power is required of the force the motor exerts on the cab via the cable? Number Units

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