Force, mass and acceleration
Grade 8 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Ari pushes a loaded wagon with 96 N against 16 N of friction. It speeds up at 4 m/s². What is its mass?
Bo pushes a box with 90 N against 30 N of friction. It speeds up at 5 m/s². What is its mass?
Esme pushes a shopping cart with 56 N against 20 N of friction. It speeds up at 2 m/s². What is its mass?
Jun doubles the push on a wagon and also doubles its load, so the mass doubles too. What happens to the acceleration?
- It grows: the bigger load helps
- It stays the same: both double
- It doubles: the push doubled
- It becomes a steady speed
Kira's sled gets half the push but carries twice the mass. What happens to its acceleration?
- It halves: the push matters most
- It moves at a slower steady speed
- It doubles: more mass speeds it
- It is one quarter as much
Luz triples the net force on the same toy robot. What happens while the force acts?
- Nothing, since the mass is the same
- It moves three times as fast, steadily
- It speeds up three times as quickly
- It speeds up a third as quickly
Pia compares two boxes pushed with 25 N each. How do their accelerations compare?
- Box B's is bigger, since its friction is less
- Box B's is bigger, since it is heavier
- Box A's is bigger: 25 ÷ 5 beats 25 ÷ 10
- They are equal
Read this first
Use this
Investigation card (test results). Question: does more force give more acceleration? Trial 1: 2 kg cart, 4 N pull, 2 m/s². Trial 2: 4 kg cart, 8 N pull, 2 m/s². Conclusion written: force does not change acceleration.
Ren checks a classmate's test. What is wrong with the conclusion?
- Two things changed at once: force and mass
- The pulls were too small to matter
- The track should have been longer
- Speed, not acceleration, should be measured
Use this
Investigation card (test results). Question: how does pulling force change a 3 kg cart's motion? Changed: pull (3 N, 6 N). Measured: the cart's speed after 1 s, starting from rest. Results: 1 m/s, 2 m/s. Conclusion written: each force gives the cart one fixed speed.
Tala reads this conclusion. What is the best correction?
- The mass changed between trials
- The cart should be lighter
- Each force gives a fixed speed, as written
- The force changed how fast speed grows
Use this
Investigation card (test results). Question: does mass change acceleration with the same pull? One trial each: 1 kg cart, 2 m/s²; 2 kg cart, 1 m/s². The pulls were not measured. Conclusion written: more mass gives less acceleration.
Zee checks this test. What makes the conclusion weak?
- The carts were too light
- Speed should be measured instead
- The pulls were not measured or repeated
- More mass should give more acceleration