A sled and rider with a combined weight of 50 kg are at rest on the top of a hill 23 m high. (a) What is their total energy at the top of the hill? ____ J (b) Assuming there is no friction, what would the total energy be on sliding halfway down the hill?  ____J

As usual, Hampus is out cycling. He is driving at 30.0 km/ h when he comes to a small hill that is 11 m high and 350 m long. Hampus and the bike weigh 95 kg together. a) What kinetic energy does Hampus have just before the hill? b) How much extra energy must Hampus produce to maintain a constant speed (30.0 km/ h) throughout the hill? c) How long does it take him to drive up the hill? d) What effect must he develop on the hill? Once at the top of the hill, the ground is flat. Hampus is tired and stops pedaling. After 12s the cycle stops. e) How big is the coefficient of friction? You can assume that is constant throughout the deceleration and that it includes both drag and rolling resistance.

M PAMP7 ** F20 A student pulls a crate of mass M up the inclined surface the distance d. The surface rises 0 degrees above the horizontal, as shown in the figure How much work does gravity do on the crate? Please use the following values: M = 11.9 kg, 0 = 26.9°, d = 5.88 m, g 9.80 m/s (PAMP716F20) a) 0612 J b) О310J c) O-612 J d) 0 686 J e) O-310 J

1. A roller-coaster car with a mass of 1200 kg starts at rest from a point 20 m above the ground. At point B, it is 9 m above the ground. [Express your answers in kilojoules (kJ).] a. What is the initial potential energy of the car? b. What is the potential energy at point B? c. If the initial kinetic energy was zero and the work done against friction between the starting point and point B is 40 000 J (40 kJ), what is the kinetic energy of the car at point B 2. The time required for one complete cycle of a mass oscillating at the end of a spring is 0.80 s. What is the frequency of oscillation?