Two positive point charges q are placed on the x axis one at x=a and one at x=-a find the electric field at x=0, derive an expression for the electric field at points on the x axis where -aa, x< -a

Which sentences describe disadvantages of burning fossil fuels instead of using hydrogen fuel cells? burning fossil fuels contributes to climate change. burning fossil fuels takes place inside expensive fuel cells. fossil fuels aren't widely available, but pure hydrogen is. fossil fuels are nonrenewable.

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

An ideal otto cycle has a compression ratio of 10.5, takes in air at 90 kpa and 40°c, and is repeated 2500 times per minute. using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kw of power.