1. On planet Tehar, the free fall acceleration is the same as that on Earth but there is also strong downward electric field with the field being uniform close to the planet's surface. A 2.00 kg ball having a charge of 5.00 mC is thrown upward at a speed of 20.1 m/s and it hits the ground after an interval of 4.10 s. What is the potential difference between the starting point and the top point of the trajectory?

2. An electron starts from rest 3.00cm from the center of a uniformly charged sphere of radius 2.00cm. If the shpere carries a total charge of 1.00 * 10^-9C, how fast will the electron be moving when it reaches the surface of the sphere?

3. A certain storm cloud has a potential difference of 1.00 * 10^8V relative to a tree. If, during a lightning storm, 50.0C of charge is transferred through this potential difference and 100% of the energy is absorbed by the tree, how much water(sap in the tree) initially at 30.0degreeC can be boiled away? Water has a specific heat of 4186J/kg degreeC, at boiling point of 100 degreeC, and a heat of vaporization of 2.26 * 10^6J/kg

4. A plastic pellet has a mass of 7.5*10^-10kg and carries a charge of 2.00 *10^-9C. The pellet is fired horizontally between a pair of oppositely charged paralled plates, as shown in the attachment, If the electric field strength between the plates is 9.2*10^4N/C and the pellet enters the plates with an initial speed of 150m/s, determine the deflection angle &. (hint this is similar to those involving the motion of a projectile under gravity)