Une barre de fer rigide de 1,80m supporte à son extrémité Aune charge
pesant 245N et à son extrémité B
une charge pesant 343N. Quelle
force faut-il exercer pour soulever la
barre et en quel point faut-il la saisir
pour qu'elle reste horizontale?

Acyclotron is used to produce a beam of high-energy deuterons that then collide with a target to produce radioactive isotopes for a medical procedure. deuterons are nuclei of deuterium, an isotope of hydrogen, consisting of one neutron and one proton, with total mass 3.34×10−27kg. the deuterons exit the cyclotron with a kinetic energy of 6.40 mev .a-what is the speed of the deuterons when they exit? b-if the magnetic field inside the cyclotron is 1.25 t, what is the diameter of the deuterons' largest orbit, just before they exit? c-if the beam current is 350 μa how many deuterons strike the target each second?