The trucks begin to move at the same speed. Which truck needs a larger force to start moving?

 - a mail truck carrying 300 pounds of mail
 - a mail truck carrying 200 pounds of mail
Look for the mail truck that is heavier.
A mail truck carrying 300 pounds of mail is heavier than a mail truck carrying 200 pounds of mail. So, the mail truck carrying 300 pounds needs a larger force to start moving at the same speed as the other mail truck.