Q. A proton (mass= 1.67 10-27 kg, charge= 1.6 10-19 C) travelling with 1.10 x10^6 m/s enters a region of space containing a uniform magnetic field of 1.4 T. What is the time t required for the proton to re-emerge into the field-free region?

Q. Block 1, of mass m_1 = 0.500 kg, is connected over an ideal (massless and frictionless) pulley to block 2, of mass m_2. Suppose that the blocks accelerate with an acceleration of magnitude a = 0.550 m/s^2 and that coefficient of kinetic friction between block 2 and the plane is mu = 0.400.Find out the mass of block 2, m_2, when theta = 30.0^circ.