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. 2.

   Bo pushes a box of books on a cart with a mass of 12 kg, and it speeds up at 3 m/s². Force = mass × acceleration. What is the net force?

   36 N
3. 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?

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

   arrows drawn to scale by size. Luz pulls an empty sled, then the same sled with a backpack, each with 4 N. Which speeds up more?

   • The empty sled
   • Neither, since 4 N is small
   • The loaded sled, since mass helps
6. 6.

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

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

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

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

8. Read this first

   Use this

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

9. 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
   • Nothing changes, since the mass is the same
   • It moves at one fixed, faster speed
   • The acceleration halves to 1 m/s²
10. 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 doubles to 4 m/s²
    • The acceleration halves to 1 m/s²
    • It keeps 2 m/s² since the box is the same
    • The box stops moving
11. 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 keeps speeding up
    • It slows down
    • It stays still
    • It moves at one steady speed