| 1. |
Mr. Bloop is giving a demonstration using two hard rubber balls. He is dropping them from his hands to the floor and measuring the width of the dents they make in a piece of polystyrene foam. The one that has the most kinetic energy when it hits leaves the widest dent. Both balls have a radius of 2 1/2 cm but their masses are different. The red ball is 11 2/3 grams and the blue on is 17 1/2 grams. If the blue one is held 2 1/3 m from the surface of the foam and the red one is held 2 1/4 m up, which one should make the larger dent? You do not need to know the value for the acceleration of gravity to solve this problem!
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| 2. |
Christian is hiking in the national park. He is on an 8 3/4-mile hike and he makes four evenly spaced rest stops along the way. At what mile of the hike does he make his last stop?
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| 3. |
Two objects (very tiny space ships actually) hit a wall. Object one applied a force of 7/13 of a Newton to the wall and object two applied a force of 3/7 of a Newton. Prove which one applied the larger force. (force = mass x acceleration)
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| 4. |
Hannah is riding her bicycle on the hike and bike trail around Village Lake. She rides 25 minutes and travels 9 2/3 miles. She then takes a 15 minutes rest. After resting (and eating an energy bar) she rides another 45 minutes and covers 14 2/3 miles. What was her average speed for the entire trip in miles per hour? (include the time she rested in the answer)
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| 5. |
The kinetic energy (KE) of an object is one-half its mass times its velocity squared (1/2 mv2). If a 2 1/6-kg ball has a velocity of 2/3 m/s, what is its KE? (hint: don't forget to square the velocity)
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| 6. |
The potential energy (J) [= Mass(kg) x Distance(m) x Acceleration of Gravity(m/s2)] of an object on earth depends on its distance from the ground. If you hold a hammer (mass = 1 3/4 kg) 120 cm from the ground, what is its potential energy? The acceleration of gravity is 9.8 m/s2. Hint: The unit for distance must be in meters when calculating potential energy.
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