Force, mass and acceleration

Answer Key - Grade 8 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   “Force arrow diagram, one dimension, arrows drawn to scale by size. Beside it:” Ari pushes a wagon with a mass of 10 kg, and it speeds up at 2 m/s². Force = mass × acceleration. What is the net force?

   20 N

2. Read this first

   Use this

   Force arrow diagram, one dimension, arrows drawn to scale by size. Box A labeled 20 kg: net force ? pointing right. Beside it:

3. 2.

   Esme pushes a shopping cart with a mass of 20 kg, and it speeds up at 4 m/s². Force = mass × acceleration. What is the net force?

   80 N
4. 3.

   Force arrow diagram, one dimension, arrows drawn to scale by size. Jun gives the same 20 N push to an empty cart and a full one. Which speeds up more?

   • Both the same, since the push is the same
   • The full cart, since it is heavier
   • The empty cart
5. 4.

   In gym, Kira pushes a soccer ball and a heavy medicine ball with the same 10 N. Which speeds up more?

   • The soccer ball
   • The medicine ball, since it has more mass
   • Both the same
6. 5.

   Milo labels a science table. Which unit goes with acceleration?

   • m/s²
   • N
   • m/s
   • kg
7. 6.

   Noah writes F = m × a on a card. Which unit goes with F, the force?

   • meters per second (m/s)
   • seconds (s)
   • kilograms (kg)
   • newtons (N)
8. 7.

   In F = m × a, which unit goes with m, the mass, Pia?

   • N
   • m/s²
   • kg
   • m

9. Use this

   Force arrow diagram, one dimension, arrows drawn to scale by size.

10. 8.

    A net force of 20 N speeds up Ren's 10 kg wagon at 2 m/s². If the net force doubles to 40 N, what happens?

    • The acceleration doubles to 4 m/s²
    • It moves at one fixed, faster speed
    • The acceleration halves to 1 m/s²
    • Nothing changes, since the mass is the same
11. 9.

    A 12 N net force speeds up a 6 kg box at 2 m/s². Tala halves the push to 6 N. What happens?

    • The acceleration halves to 1 m/s²
    • The box stops moving
    • The acceleration doubles to 4 m/s²
    • It keeps 2 m/s² since the box is the same
12. 10.

    Beside it: speeding up at 2 m/s². A steady 30 N net force acts on Zee's 15 kg cart for 3 s. What does the cart do during those 3 s?

    • It slows down
    • It keeps speeding up
    • It stays still
    • It moves at one steady speed