NUMS — Medical & Dental Entry Test

NUMS Physics — Mechanics: Motion, Force, Work and Energy (Set 2)

Take the NUMS Physics — Mechanics: Motion, Force, Work and Energy (Set 2): 30 multiple-choice questions (40 minutes) with instant scoring and a full…

What this test covers

30 NUMS Physics

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

Q1. Two forces of 5 N and 12 N act on the same point. Which value could NOT be the magnitude of their resultant?
- A. 13 N
- B. 17 N
- C. 7 N
- D. 19 N ✓
Answer: D. 19 N
Explanation: The resultant of two forces lies between their difference and their sum: 7 N ≤ R ≤ 17 N (13 N when they are perpendicular). 19 N is outside this range.
Q2. A force F = (3î + 4ĵ) N moves a trolley through a displacement d = (2î − ĵ) m. How much work is done by the force?
- A. 6 J
- B. 10 J
- C. −4 J
- D. 2 J ✓
Answer: D. 2 J
Explanation: W = F·d = (3)(2) + (4)(−1) = 6 − 4 = 2 J.
Q3. For the unit vectors î, ĵ and k̂ of a right-handed coordinate system, what is ĵ × î?
- A. k̂
- B. 0
- C. 1
- D. −k̂ ✓
Answer: D. −k̂
Explanation: î × ĵ = k̂, and the cross product is anti-commutative, so ĵ × î = −k̂.
Q4. An ambulance pulls away from rest with a uniform acceleration of 3 m s⁻². What distance does it cover by the time its speed reaches 24 m s⁻¹?
- A. 48 m
- B. 96 m ✓
- C. 72 m
- D. 192 m
Answer: B. 96 m
Explanation: v² = u² + 2as → 24² = 0 + 2 × 3 × s, so s = 576/6 = 96 m.
Q5. A body starts from rest and moves with uniform acceleration 4 m s⁻². What distance does it cover during the 3rd second only?
- A. 18 m
- B. 8 m
- C. 12 m
- D. 10 m ✓
Answer: D. 10 m
Explanation: Distance in 3 s = ½ × 4 × 9 = 18 m; in 2 s = ½ × 4 × 4 = 8 m; so during the 3rd second it covers 18 − 8 = 10 m.

The other 25 questions

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Q6. A ball is kicked at 20 m s⁻¹ at 30° above the horizontal. What maximum height does it reach? (g = 10 m s⁻², ignore air resistance)
- A. 15 m
- B. 10 m
- C. 20 m
- D. 5 m
Q7. A ball is kicked at 20 m s⁻¹ at 30° above level ground. What is its horizontal range? (g = 10 m s⁻²)
- A. 40.0 m
- B. 17.3 m
- C. 20.0 m
- D. 34.6 m
Q8. A ball is thrown vertically upward at 30 m s⁻¹. What maximum height does it reach and how long does it take to get there? (g = 10 m s⁻²)
- A. 90 m in 3 s
- B. 45 m in 6 s
- C. 30 m in 3 s
- D. 45 m in 3 s
Q9. A 60 kg patient stands on a weighing scale inside a hospital lift that is accelerating upward at 2 m s⁻². What does the scale read? (g = 10 m s⁻²)
- A. 480 N
- B. 720 N
- C. 600 N
- D. 120 N
Q10. A book rests on a table. According to Newton's third law, what is the reaction to the gravitational pull of the Earth on the book?
- A. The gravitational pull of the book on the Earth
- B. The weight of the table
- C. The upward push of the table on the book
- D. The downward push of the book on the table
Q11. A 0.5 kg ball moving at 20 m s⁻¹ is caught and brought to rest in 0.1 s. What average force does the catcher apply?
- A. 200 N
- B. 100 N
- C. 10 N
- D. 1000 N
Q12. A 2 kg trolley moving at 6 m s⁻¹ collides with a stationary 4 kg trolley and they stick together. How much kinetic energy is lost?
- A. 12 J
- B. 0 J
- C. 36 J
- D. 24 J
Q13. A rocket ejects exhaust gas at 2000 m s⁻¹ relative to itself at a rate of 5 kg s⁻¹. What thrust does it produce?
- A. 2.0 × 10³ N
- B. 400 N
- C. 1.0 × 10⁴ N
- D. 1.0 × 10³ N
Q14. A stone tied to a string is whirled in a horizontal circle at constant speed. How much work does the tension in the string do in one revolution?
- A. 2πr × T
- B. It depends on the mass of the stone
- C. mv², because the force is centripetal
- D. Zero, because the tension is always perpendicular to the velocity
Q15. A 2 kg mass falls freely from rest through 5 m. What is its speed just before it hits the ground? (g = 10 m s⁻²)
- A. 50 m s⁻¹
- B. 10 m s⁻¹
- C. 5 m s⁻¹
- D. 100 m s⁻¹
Q16. An ambulance cruises at a steady 20 m s⁻¹ against a total resistive force of 500 N. What power does its engine deliver?
- A. 10 kW
- B. 2.5 kW
- C. 25 kW
- D. 1 kW
Q17. A car's suspension spring has a force constant of 4000 N m⁻¹. How much elastic energy does it store when compressed by 5 cm?
- A. 5 J
- B. 100 J
- C. 0.5 J
- D. 10 J
Q18. A 0.5 kg ball on a string moves in a horizontal circle of radius 2 m at 4 m s⁻¹. What centripetal force acts on it?
- A. 16 N
- B. 4 N
- C. 2 N
- D. 8 N
Q19. A bucket of water is swung in a vertical circle of radius 2.5 m. What is the minimum speed at the top of the circle for the water to stay in the bucket? (g = 10 m s⁻²)
- A. 2.5 m s⁻¹
- B. 7.1 m s⁻¹
- C. 25 m s⁻¹
- D. 5 m s⁻¹
Q20. A wheelchair wheel of radius 0.3 m rotates at 20 rad s⁻¹ without slipping. What is the linear speed of the wheelchair?
- A. 6 m s⁻¹
- B. 60 m s⁻¹
- C. 66.7 m s⁻¹
- D. 0.015 m s⁻¹
Q21. A solid disc and a ring of the same mass and radius are released together from the top of the same incline and roll without slipping. Which reaches the bottom first?
- A. Both arrive together, since mass and radius are equal
- B. The ring, because its mass is at the rim
- C. The disc, because a smaller fraction of its energy goes into rotation
- D. The ring, because it has a larger moment of inertia
Q22. The rotor of a dental air-turbine drill has a moment of inertia of 4 × 10⁻⁶ kg m² and spins at 500 rad s⁻¹. What is its rotational kinetic energy?
- A. 1 × 10⁻³ J
- B. 1 J
- C. 0.25 J
- D. 0.5 J
Q23. A spanner 0.5 m long is pushed at its end with a force of 20 N acting at 30° to the spanner handle. What torque is produced about the bolt?
- A. 5 N m
- B. 40 N m
- C. 10 N m
- D. 8.7 N m
Q24. Why are buses and cranes designed with a wide wheel base and a low centre of gravity?
- A. It increases stability, as a larger tilt is needed before the weight acts outside the base
- B. It reduces the weight of the vehicle
- C. It increases the speed of the vehicle
- D. It reduces the normal reaction force
Q25. At what height above Earth's surface does the acceleration due to gravity fall to one quarter of its surface value? (R = Earth's radius)
- A. 4R
- B. R/2
- C. R
- D. 2R
Q26. Which condition must a geostationary communication satellite satisfy?
- A. It orbits above the equator, west to east, with a period of 24 hours
- B. It orbits at any height as long as its period is 24 hours
- C. It stays at rest in space above one city
- D. It orbits over the poles with a period of 12 hours
Q27. According to Kepler's third law, if the orbital radius of a planet were four times that of another, how would its orbital period compare?
- A. 16 times longer
- B. 4 times longer
- C. 2 times longer
- D. 8 times longer
Q28. A blood pressure reading of 120 mmHg is converted to SI units. What is it approximately? (ρ of mercury = 13 600 kg m⁻³, g = 9.8 m s⁻²)
- A. 16 kPa
- B. 120 kPa
- C. 160 kPa
- D. 1.6 kPa
Q29. Impulse is defined as force multiplied by the time for which it acts. Which quantity has the same dimensional formula as impulse?
- A. Force
- B. Linear momentum
- C. Power
- D. Kinetic energy
Q30. A vernier calliper has a least count of 0.1 mm and a micrometer screw gauge has a least count of 0.01 mm. Which statement is correct?
- A. The screw gauge gives more precise readings
- B. Both are equally precise
- C. The vernier calliper gives more precise readings
- D. Precision does not depend on least count