Science: Practice Problems Flashcards
An Olympic diver has a mass of 100kg, and he is going to dive into a pool from a height of 3 meters.
How much potential energy does he have?
100kg x 3m = 300
300 x 10m/s = 3000
A: 3000J
Your brother has a mass of 15kg. What is his weight in Newtons?
15kg x 10m/s = 150
A: 150 Newtons
A gorilla is 100kg. It jumps from a tree which is 5 meters high. If all of its gravitational potential energy is changed into kinetic energy, how much kinetic energy will it have when it hits the ground?
How fast will be moving after 2 seconds after jumping?
100kg x 5m x 10m/s = 5000J
A = 5000J
2s x 10m/s = 20m/s
Two identical blocks are heated to different temperatures. The blocks are placed so that they touch each other. Heat can flow from one block to another but cannot escape from the blocks.
Block 1: 4F
Block 2: 32F
Later, the temperature of each block is measured again. Which pair of temperatures is possible?
A)
Block 1: 6F
Block 2: 30F
B)
Block 1: 19F
Block 2: 17F
C)
Block 1: 0F
Block 2: 28F
D)
Block 1: 4F
Block 2: 4F
The correct answer is A.
The answer cannot be B, because once Block 2 transfers enough heat to Block 1 so that Block 1 has the same temperature, it cannot continue to transfer heat for Block 1 to have higher temperature than Block 2.
The answer cannot be C because Block 1 cannot have lower temperature than it started with when Block 2 is transferring heat to it.
The answer cannot be D because it cannot be that both Block 1 and 2 have lower temperature than they started with.
Two identical blocks are heated to different temperatures. The blocks are placed so that they touch each other. Heat can flow from one block to another but cannot escape from the blocks.
Block 1: 133F
Block 2: 92F
Later, the temperature of each block is measured again. Which pair of temperatures is possible?
A)
Block 1: 105F
Block 2: 64F
B)
Block 1: 107F
Block 2: 118F
C)
Block 1: 107F
Block 2: 92F
D)
Block 1: 130F
Block 2: 95F
The correct answer is D.
The answer cannot be A because Block 2 cannot have lower temperature than it started with when Block 1 is transferring heat to it.
The answer cannot be B, because once Block 1 transfers enough heat to Block 2 so that Block 2 has the same temperature, it cannot continue to transfer heat for Block 2 to have higher temperature than Block 1.
The answer cannot be C, because once Block 1 transfers heat to Block 2, Block 2 cannot stay at the same temperature.
Draw a series circuit with 1 battery, 1 switch and 3 bulbs.
Show me on paper
Draw a parallel circuit with 1 battery, 1 switch and 2 bulbs
Show me on paper
Draw heat diagram
Do on paper
