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• Users: PeterPeter
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1. ### RELATIVITY: Co-ordinates of events

Thanks to you all. I think I'm starting to get the basics of SR!
2. ### RELATIVITY: Co-ordinates of events

I have reworked using a ruler length of L instead of 1m. I get: 1. The right end of the ruler passes the observer (in the observer's frame) (0,0) 2. The left end of the ruler passes the observer (in the observer's frame) (0,L/(u*gamma)) 3. The observer passes the right end of the ruler (in...
3. ### RELATIVITY: Co-ordinates of events

Thanks. I was expecting to get something like length/gamma ie length contraction!
4. ### RELATIVITY: Co-ordinates of events

Homework Statement A meter ruler moves at velocity u to the right past a stationary observer. The observer is at (0,0) in his rest frame. Give the (x,t) co-ordinates of the following events. 1. The right end of the ruler passes the observer (in the observer's frame) 2. The left end of the...
5. ### Special Relativity: Relative velocity

Homework Statement I know that if you have 2 observers, "A", one at rest and the other "B" moving wrt "A" and if the moving observer shoots a projectile, then we can calculate the velocity of the projectile wrt "A" using the standard equation shown below. I was thinking what equation would...
6. ### Find the velocity of the 14kg mass just before it hits the ground

Yes! Exactly! Here are my current thoughts. Taking down as positive: For 8Kg weight, where a is the acceleration of the 8Kg: 8a=-T1+8g For 14Kg weight where b is the acceleration of the 14Kg: 14b=14g-T2 For Pulley (since the tension on both sides of the string acts down)...
7. ### Find the velocity of the 14kg mass just before it hits the ground

Oops. Seems I skipped a step! Thanks. Intuitively 8a=T1-8g 14a=14g-T2 T1=T2 => (8+14)a= 14g-8g which gives the correct answer after a bit of algebra. ONE FURTHER QUESTION If the down direction is taken as positive, shouldn't these equations be... (T1 act upwards 8a=-T1+8g 14a=14g-T2 T1=-T2...
8. ### Find the velocity of the 14kg mass just before it hits the ground

Homework Statement A 14kg mass is attached to one side of a vertical pulley and an 8kg to the other. The 14kg mass is 5m above the ground. The 8kg is just resting on the ground. The pulley is frictionless and weightless. Find the velocity of the 14kg mass just before it hits the...