Suppose a spring has a relaxed length of 28.3 cm. The simulation refers to this as the natural length. This is the length of the spring when it is not stretched nor compressed by any force. When you hang a mass of 550 g on the vertical spring, the spring stretches to a new length of 38.2 cm. What is an estimate of the spring constant, k, of the spring? (Enter your answer in N/m.) Measuring only one value is not a good way to get the value, but you can an idea of the approximate size.

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

Acrow drops a 0.11kg clam onto a rocky beach from a height of 9.8m. what is the kinetic energy of the clam when it is 5.0m above the ground? what is its speed at that point?

Which of the choices below is one of the primary gases found in the atmosphere? a. helium b. carbon dioxide c. nitrogen d. argon