john doe operates a crane that can pick up 3.0 tons of excavated earth in an hour. John's wages are $35 per hour. What, then, is the cost of picking up 85kg of excavated earth?

When a neutral charge, comes into contact with a positive charge they repel each other nothing happens the neutral charge becomes negative they attract each other

Could someone . i have tried to solve myself but my calculation is off

Which of the following correctly describes what happens when an atomic bomb explodes? small pieces of fissionable material are joined and form a body with a mass greater than the critical mass, the relative number of neutrons escaping decreases, and a chain reaction and explosion result. large pieces of fissionable matter are brought together quickly and form a body with a mass smaller than the critical mass, the relative number of escaping neutrons increases, and a chain reaction and explosion result.