Abeam of π+ particles (mπ = 140 mev/c2) is accelerated to a momentum of pπ+ = 3.1 gev/c in the laboratory frame. a π+ particle decays into a positive muon (mμ = 105 mev/c2) and a muon neutrino (mνμ = 0 mev/c2).

a. what is the energy of the muon in the rest frame of the π+?
b. what is the energy of the muon in the laboratory frame if it is found traveling in the beam direction?
c. what is the energy of the muon in the laboratory frame if it is found traveling at and angle of 250 mrad with respect to the beam direction?

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 790 n/m. it is initially at rest on an inclined plane that is at an angle of 28 degrees with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is k = 0.14. in the initial position, where the spring is compressed by a distance of a = 0.18 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

An athlete is holding 24 lb of weights at a height of 6 inches above the stack as shown. to lower the weights, she applies a constant force of 5 lb to the handle. determine the velocity of the weights immediately before they hit the stack.

Sort the images based on whether there's a force of attraction or repulsion between the magnets shown. attraction repulsion