A proton with mass 1.67 x 10−27 kg and charge +1.6. x 10−19 C, is sent with velocity 2.3 x 104 m/s in the +x direction into a region where there is a uniform electric field of magnitude 780 V/m in the +y direction. What must be the magnitude and direction of the uniform magnetic field in the region if the proton is to pass through undeflected?
Assume that the magnetic field has no x-component and neglect gravitational effects.

Agardener uses a wheelbarrow to move soil from a truck to his garden. on the first trip from the truck to the garden, the wheelbarrow is half-full of soil and the gardener applies a certain force to cause it to accelerate. on the second trip, the wheelbarrow is full of soil. although the gardener applies the same amount of force to the wheelbarrow, he cannot move it with the same rate of acceleration. what should the gardener do to move the wheelbarrow at the same rate of acceleration for the second trip?

Look at the potential energy diagram for a chemical reaction. which statement correctly describes the energy changes that occur in the forward reaction?

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?