1. A spring has a spring stiffness constant, K, of 440N/m. How much must this spring be stretched to store 25 J of potential energy?

2. By how much does the GPE of a g4.0 kg pole vaulter change if its center of mass rises about 4.0 m during the jump?

3. A 1200-kg car rolling on a horizontal surface has speed 65 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is the spring stiffness constant of the spring? Hint:The KE of the car is completely converted into EPE

4. A novice skier, starting from rest, slides down a frictionless 35.0(deg) incline whose vertical height is 185 m. How fast is she going when she reaches the bottom?

5. A projectile is fixed at an upward angle of 45.0(deg) from the top of a 265 m cliff with a speed of 185 m/s/ What will be its speed when it strikes the ground below? Hint: What is the change in PE from when the projectile was launched to when it strike the ground? What was the initial KE of the projectile? This depends only on the magnitude of the velocity. The horizontal and vertical components of the velocity do not matter.

Labels: Assignments

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