Directions: Read each sentence carefully. Write the letter of the correct answer on the answer sheet provided.
1. What is produced when two surfaces rub against each other?
A. air
B. pressure
C. motion
D. friction
2. Which surface increases friction?
A. polished B. rough
C. lubricated
D. shiny
3. What causes falling objects to fall?
A. speed
B. gravity
C. acceleration
D. wind
4. Which surface decreases friction?
A. smooth B. rugged
C. rough
D. rocky
5. Why do you move faster when running down a hill?
A. Gravity pulls you up.
C. Gravity pulls you down.
B. Wind pushes you back.
D. Wind pulls you.​