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You need to lift a 200 kg box 5 meters, but it is too heavy. You decide to push it up an incline that makes a 25o angle with the ground. With what force do you need to push the box? You can estimate your distance from a lightning storm by watching for a lightning flash and then counting in one-second intervals using the general rule that you are 1 km away for every 3 s you count. Explain why this rule works. Estimate the distance from a lightning storm if it takes 8 s (exactly) for the sound of the thunder to reach you after you see a flash of lightning. Assume that the temperature is 21oC. (The speed of light is approx. 2.99 x 108 m/s.)