2 Physics Questions

[b0red]

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 25^o 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 21^oC. (The speed of light is approx. 2.99 x 10⁸ m/s.)

 

 

 

 

[swansont]

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Moderator Note

 

Since these look very, very, very much like HW questions, moved. Show us what you've done to solve the problems, and you'll get help.

 

Problem 1 looks like it needs a free-body diagram.