10. Conservation of Energy

Which of the following is the best example of the conservation of energy principle in action?

Which of the following is the best example of the law of conservation of energy?

Which of the following best states the law of conservation of energy?

A sled starts from rest at the top of the frictionless, hemispherical, snow-covered hill shown in FIGURE P10.56. a. Find an expression for the sled's speed when it is at angle ϕ .

Which of the following is an example of conservation of energy resources?

Which statement best describes the law of conservation of energy?

A 12 kg weather rocket generates a thrust of 200 N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 550 N/m, is anchored to the ground. After the engine is ignited, what is the rocket’s speed when the spring has stretched 40 cm?

A sled is initially given a shove up a frictionless 18.0° incline. It reaches a maximum vertical height 1.22 m higher than where it started at the bottom. What was its initial speed?

Which of the following best describes the requirement of the law of conservation of energy in a closed system?

A novice skier, starting from rest, slides down an icy frictionless 8.0° incline whose vertical height is 115 m. How fast is she going when she reaches the bottom?

(I) A 16.0-kg child descends a slide 2.20 m high and, starting from rest, reaches the bottom with a speed of 1.15 m/s. How much thermal energy due to friction was generated in this process?

Which of the following scenarios best adheres to the law of conservation of energy ($E=\mathrm{constant}$)?

A 62-kg trampoline artist jumps upward from the top of a platform with a vertical speed of 4.5 m/s. How fast is he going as he lands on the trampoline, 2.0 m below (Fig. 8–32)? <IMAGE>

A block of mass m slides down a frictionless track, then around the inside of a circular loop-the-loop of radius R . From what minimum height h must the block start to make it around without falling off? Give your answer as a multiple of R.

In the high jump, the kinetic energy of an athlete is transformed into gravitational potential energy without the aid of a pole. With what minimum speed must the athlete leave the ground in order to lift his center of mass 2.10 m and cross the bar with a speed of 0.50 m/s?