Force is measured in newtons and Newton's first law covers objects staying at rest or moving at constant velocity, so this Year 9 sheet opens with the unit and the rest-motion law. F = m × a and the 7 N result appear in the answers.
Key Takeaways
The unit of force is the newton (Q1).
Newton's first law covers uniform motion without a resultant force (Q2).
Q3 records F = m × a.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.What unit is force measured in?
(a) newton(b) joule(c) watt(d) pascal
2.Which of Newton's laws states that an object stays at rest or moves at constant velocity unless acted on by a resultant force?
(a) First law(b) Second law(c) Third law(d) Law of gravitation
3.Which formula represents Newton's second law of motion?
(a) F = m × a(b) W = F × d(c) P = W ÷ t(d) E = m × c × Δθ
4.A book rests on a table. Which force balances the weight of the book?
(a) The normal (support) force(b) Friction(c) Tension(d) Air resistance
5.Two forces of 3 N and 4 N act on an object in the same direction. What is the resultant force?
(a) 1 N(b) 7 N(c) 12 N(d) 5 N
6.Friction always acts to oppose the motion of an object. Which statement about friction is correct?
(a) It always acts opposite to the direction of motion(b) It always acts in the direction of motion(c) It always acts upwards(d) It only acts on moving objects
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Define a force and give its unit.
8.State Newton's first law of motion.
9.Write down the formula linking force, mass and acceleration.
10.State Newton's third law of motion.
11.Define weight and give the formula used to calculate it.
12.Explain the difference between mass and weight.
13.What is a resultant force?
14.What two effects can a force have on an object?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A force of 10 N is applied to a mass of 5 kg. Using F = m × a, calculate the acceleration of the mass.
16.Calculate the weight of a 3 kg object on Earth. Use g = 10 N/kg and the formula W = m × g.
17.A resultant force of 20 N gives an object an acceleration of 5 m/s². Using F = m × a, find the mass of the object.
18.A 60 N force acts on an 8 kg mass. Using a = F ÷ m, calculate the acceleration.
19.A 12 N force acts on a 2 kg mass. A friction force of 4 N opposes the motion. Using F = m × a, find the resultant force and the acceleration.
20.An object accelerates at 3 m/s² under a resultant force of 15 N. Using F = m × a, determine the mass of the object.
Answer Key
1. a) newton
2. a) First law
3. a) F = m × a
4. a) The normal (support) force
5. b) 7 N
6. a) It always acts opposite to the direction of motion
7. Refer to solution guide.
8. Refer to solution guide.
9. Refer to solution guide.
10. Refer to solution guide.
11. Refer to solution guide.
12. Refer to solution guide.
13. Refer to solution guide.
14. Refer to solution guide.
15. Refer to solution guide.
16. Refer to solution guide.
17. Refer to solution guide.
18. Refer to solution guide.
19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
What unit is force measured in?
The newton, option (a) in this worksheet (Q1).
Which law states that objects keep constant velocity without a resultant force?
The first law, option (a) in this worksheet (Q2).
How is Newton's second law written?
F = m × a, option (a) in this worksheet (Q3).
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