- #1
k4wedi
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1) A mathematical pendulum , length L= 0.61 m oscillates in a uniformly accelerating vehicle. The acceleration is horizontal and equal to 3.2 m/ s^2 The period of oscillations is?
I don't know where to put in the acceleration when it is horizontal. I thought that if I just added the two vectors mg and ma I would get the answer but that turned out to be the same as if I was moving up vertically..
2) At what speed v should an object move with respect to a system S in order that its density measured from S is n=1.088 times greater then its proper density ( i.e. density measured in a system in which object is at rest ). Express your result as a ratio v/c .
I got it so that: 1.088(RestDensity) = (RestDensity) / [ 1 - (v/c)^2 ]
After working it out I got my answer to be 0.284... but the "right" answer is 0.878.. that doesn't make any sense to me since you'd have to move at almost 90% the speed of light just to increase 1.088 times your rest density??
3) Calculate the speed at which the kinetic energy of a particle is equal to its rest energy. Express your result as v/c
This.. I got it to be 0.84 and the "right" answer is 0.87..
I used E^2 = p^2 * c^2 + m^2*c^4; where m is the rest mass and p is the momentum
equated p^2*c^2 to m^2*c^4 and solved for v by subbing p = mv where the m in this case is the relativisic mass. Is that just plain wrong?
Much thanks to anyone who can help, I've been at these problems for a while.. :<
I don't know where to put in the acceleration when it is horizontal. I thought that if I just added the two vectors mg and ma I would get the answer but that turned out to be the same as if I was moving up vertically..
2) At what speed v should an object move with respect to a system S in order that its density measured from S is n=1.088 times greater then its proper density ( i.e. density measured in a system in which object is at rest ). Express your result as a ratio v/c .
I got it so that: 1.088(RestDensity) = (RestDensity) / [ 1 - (v/c)^2 ]
After working it out I got my answer to be 0.284... but the "right" answer is 0.878.. that doesn't make any sense to me since you'd have to move at almost 90% the speed of light just to increase 1.088 times your rest density??
3) Calculate the speed at which the kinetic energy of a particle is equal to its rest energy. Express your result as v/c
This.. I got it to be 0.84 and the "right" answer is 0.87..
I used E^2 = p^2 * c^2 + m^2*c^4; where m is the rest mass and p is the momentum
equated p^2*c^2 to m^2*c^4 and solved for v by subbing p = mv where the m in this case is the relativisic mass. Is that just plain wrong?
Much thanks to anyone who can help, I've been at these problems for a while.. :<