Conservation of energy-Practice probelms-Gr9 &10

1. Starting from rest, a child zooms down a frictionless slide from an initial height of 3.00 m. What is her speed at the bottom of the slide? Assume she has a mass of 25.0 kg.
2. A 1.25-kg mass is connected to a spring that has a constant of 25.0 N/m and is displaced 4.00 m before being released. Find the maximum velocity of the mass during its cycle.
3. If the spring of a jack-in-the-box is compressed a distance of 8.00 cm from its relaxed length and then released, what is the speed of the toy head when the spring returns to its natural length? Assume the mass of the toy head is 50.0 g, the spring constant is 80.0 N/m, and the toy head moves only in the vertical direction. Also disregard the mass of the spring. (Hint: Remember that there are two forms of potential energy in the problem.)
4. An Olympic runner leaps over a hurdle. If the runner’s initial vertical speed is 2.2 m/s, how much will the runner’s centre of mass be raised during the jump?
5. A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 1.9 m/s. What is the initial height of the bob?
6. A bird is flying with a speed of 18.0 m/s over water when it accidentally drops a 2.00 kg fish. If the altitude of the bird is 5.40 m and friction is disregarded, what is the speed of the fish when it hits the water?
7. A 755 N diver drops from a board 10.0 m above the water’s surface. a. Find the diver’s speed 5.00 m above the water’s surface,
b. find the diver’s speed just before striking the water.
c. If the diver leaves the board with an initial upward speed of 2.00 m/s, then find the diver’s speed when striking the water.
Work, energy and power playlist
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