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?
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 stays the same: both double
- It becomes a steady speed
- It grows: the bigger load helps
- It doubles: the push doubled
Kira's sled gets half the push but carries twice the mass. What happens to its acceleration?
- It is one quarter as much
- It halves: the push matters most
- It doubles: more mass speeds it
- It moves at a slower steady speed
Luz triples the net force on the same toy robot. What happens while the force acts?
- It moves three times as fast, steadily
- Nothing, since the mass is the same
- It speeds up a third as quickly
- It speeds up three times as quickly
Read this first
Use this
Force arrow diagram, one dimension, arrows drawn to scale by size. Box A labeled 10 kg: push 30 N pointing right; friction 10 N pointing left. Box B labeled 20 kg: push 30 N pointing right; friction 0 N pointing left.
Milo compares two carts. Which has the greater acceleration?
- The same, since both get 30 N pushes
- Cart B, since it has no friction
- Cart B, since it has more mass
- Cart A
Noah compares two sleds. Which has the greater acceleration?
- Sled B
- Sled A, since it is heavier
- Sled A, since its pull is bigger
- They are equal
Pia compares two boxes pushed with 25 N each. How do their accelerations compare?
- Box A's is bigger: 25 ÷ 5 beats 25 ÷ 10
- Box B's is bigger, since it is heavier
- Box B's is bigger, since its friction is less
- They are equal
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 cart should be lighter
- The force changed how fast speed grows
- The mass changed between trials
- Each force gives a fixed speed, as written
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