A constant force accelerates a body, until the body uses up all the power of the force.

A spaceship located in deep space fires its rockets so that they exert a thrust of 1,000 N on the ship. Which of the following describes the motion of the spaceship with its rockets on? Explain your choice.

a. It will speed up initially, and then reach a final constant speed as time goes by.

b. It will speed up initially, and its acceleration will get smaller as time goes by.

c. It will speed up initially, and its acceleration will remain the same as time goes by.

d. It will speed up initially, and its acceleration will increase as time goes by.

e. Can't be answered without the mass of the spaceship.

 

 Students who suffer from this misconception will answer either a or b.

 

Related misconceptions/student difficulties that may arise in the question:

An object with a constant net force will have a constant speed.

Students fail to see acceleration as the ratio Dv/Dt.