1. Questions1-3 refer to the following material.

An isolated，neutral lambda particle(∧^o)is moving to the right with speed v. It then decays into a proton and pion(∧^o -> P⁺ + π).The  following are the masses of the three particles:

Lambda:1115.7 MeV／c²

Proton：938.3 MeV/ c²

Pion:139.6 MeV／c²

How much energy is released when the ∧^o decays？

2. Which of the following indicate show the total linear momentum of the ∧^o  particles after the decay compares to the linear momentum of the before the decay and explains why？

3. At some later time，the proton and pion are both moving to the right in the plane of the page when they enter a magnetic field directed out of the page. Which of the following describes the directions of the magnetic forces on the proton and pion at the instant they enter the field？

4. Questions 4-7 refer to the following material.

The figure above on the left represents the horizontal electric field near the center of two large, vertical parallel plates near Earth’s surface. The plates have height h and length l, and they are separated by a distance w, as shown on the right. The field has magnitude E.

A small object with mass m= and charge +q, where m=qE/g，is released from rest at a point midway between the plates，

Points R,S,T,  and U are located between the plates as shown in the figure above, with points R and T equidistant from point S. Let V_RS, V_ST, V_TU，and V_RU, be the magnitudes of the electric potential differences between the pairs of points. How do the magnitudes of these potential differences compare？

5. After the object is released from rest, which of the paths shown in the figure above is a possible trajectory for the object？

6. Under which of the following new conditions could the gravitational force on the  object be neglected？

7. The speed of a proton moving in an electric field changes from v_i to v_f over a certain time interval. Let the mass and charge of the proton be denoted as m_p and e. Through what potential difference did the proton move during the interval?

8.

Four objects, each with charge +q, are held fixed on a square with sides of length d， as shown in the figure above. Objects X and Z are at the midpoints of the sides of the square. The electrostatic force exerted by object W on object X is F. What is the magnitude of the net force exerted on object X by objects W,Y,and Z？

9. lsolines of potential are drawn for the gravitational field of the Sun-Mercury system. The  pattern of  the isolines is identical to the pattern of equipotential lines for a system of two electrically charged objects with which of the following properties？

10.

The figure above represents the random orientations of the magnetic dipoles in a block of iron and a block of lead. Iron is ferromagnetic and lead is diamagnetic. The two blocks are placed in a magnetic field that points to the right. Which of the following best represents the orientations of the dipoles when the field is present？