## 02.3. kinematics

Question Number. 1. For a car weighing 1000 N, what force would be required to accelerate the car to 3 ms-2.

Option A. 3270 N.

Option B. 305.8 N.

Option C. 3000 N.

Correct Answer is. 305.8 N.

Explanation. F = ma F = 1000/9.81 * 3 F = 305.8 N (The 'divide by' 9.81 is necessary to convert the 1000 N into a mass (in kg)).

Question Number. 2. A time period of 10 microseconds is equal to a frequency of.

Option A. 100 kHz.

Option B. 10 kHz.

Option C. 1 Mhz.

Correct Answer is. 100 kHz.

Explanation. Frequency = 1/time period. 1/0.00001 = 100,000 = 100 kHz.

Question Number. 3. The SI unit of acceleration is the.

Option A. metre per second squared (m/s2).

Option B. metre per second (m/s).

Option C. square metre (m2).

Correct Answer is. metre per second squared (m/s2).

Explanation. NIL.

Question Number. 4. If a body starts at rest and reaches 84 m/s in 3 seconds, its acceleration is.

Option A. 28 m/s2.

Option B. 14 m/s2.

Option C. 252 m/s2.

Correct Answer is. 28 m/s2.

Explanation. Acceleration = change in speed / time.

Question Number. 5. The SI unit of velocity is the.

Option A. metre per second squared (m/s2).

Option B. metre per second (m/s).

Option C. metre (m).

Correct Answer is. metre per second (m/s).

Explanation. NIL.

Question Number. 6. An aircraft flies 1350 nmiles in 2h 15mins. What is the average speed?.

Option A. 600 nmiles/hour.

Option B. 600 miles/hour.

Option C. 150 nmiles/hour.

Correct Answer is. 600 nmiles/hour.

Explanation. Average speed = distance/time = 1350/2.25 = 600 nm/h.

Question Number. 7. A spring extends 7 cm to the ground and back again 20 times a minute. What is the period?.

Option A. 7 cm.

Option B. 3 seconds.

Option C. 1/3 cycle.

Correct Answer is. 3 seconds.

Explanation. Frequency = 20/60 = 1/3 Hz. Time period = 1/f = 3 seconds.

Question Number. 8. A cyclist goes from rest to 50 m/s in 5 seconds. What is the average acceleration?.

Option A. 10 m/s2.

Option B. 12 m/s2.

Option C. 8 m/s2.

Correct Answer is. 10 m/s2.

Explanation. Acceleration = change in speed / time.

Question Number. 9. What is the period of a frequency of 4 Hz?.

Option A. 8 seconds.

Option B. 0.25 seconds.

Option C. 4 seconds.

Correct Answer is. 0.25 seconds.

Explanation. Period = 1/f.

Question Number. 10. A dot rotates around the circumference of a circle. If the vertical position of this dot is plotted on a graph with respect to time the result will be.

Option A. a linear motion.

Option B. a transverse waveform.

Option C. a sinusoidal waveform.

Correct Answer is. a sinusoidal waveform.

Explanation. This is why an AC generator produces a sine wave frequency.

Question Number. 11. A freely falling body, falling from a height of 2km, and assuming g = 10m/s2, will strike the ground in a time of.

Option A. 400s.

Option B. 80s.

Option C. 20s.

Correct Answer is. 20s.

Explanation. From the equations of motion s = ut + 1/2at2. If it starts at rest u (and hence ut) is zero. Use s = 2000 m, plug in the numbers and transpose for t.

Question Number. 12. What is the angular velocity of a shaft rotating at 300rpm in radians/second?.

Option A. 10π radians/second.

Option B. 2π radians/second.

Option C. 5π radians/second.

Correct Answer is. 10π radians/second.

Explanation. velocity = 2π(RPM)/60 = 2π * 300/60 = 10π radians/second.

Question Number. 13. The force that acts on a body to cause it to rotate in a circular path is called the.

Option A. centripetal force.

Option B. centrifugal force.

Option C. inertia force.

Correct Answer is. centripetal force.

Explanation. Centripetal' force is the force pulling the rotating object towards the centre of rotation. 'Centrifugal' force is the equal and opposite reaction.

Question Number. 14. An aircraft of 2 metric tonnes uses 800 kilojoules kinetic energy to make an emergency stop. Its brakes apply a force of 10 kiloNewtons. What distance does it travel before it comes to a stop?.

Option A. 40m.

Option B. 800m.

Option C. 80m.

Correct Answer is. 80m.

Explanation. Energy = Force * Distance. 800,000J = 10,000N x Distance. Distance = ??.

Question Number. 15. A body rotating at an angular velocity of 5 radians/sec, with a radius of 5 metres has a speed of.

Option A. 5π metres per second.

Option B. 5 metres per second.

Option C. 25 metres per second.

Correct Answer is. 25 metres per second.

Explanation. velocity = Radius * Omega (Omega = radians/sec). V = 5 * 5 = 25 m/s.

Question Number. 16. A mass of 400 kg moves 27metres, with a force of 54N, what is the work produced?.

Option A. 1458 J.

Option B. 583.2 KJ.

Option C. 10.1 KJ.

Correct Answer is. 1458 J.

Explanation. Work = Force x Distance = 54 * 27 = 1458 J. It is not moving under gravity so the 400 kg is a red herring.

Question Number. 17. A mass on a spring nearly hits the ground 20 times a minute, its frequency is.

Option A. 3 cycles per second.

Option B. 1/3 cycle per second.

Option C. 20 cycles per second.

Correct Answer is. 1/3 cycle per second.

Explanation. cycles per minute = 20/60 cycles per second = 2/6 = 1/3 cycle per second.

Question Number. 18. A body travelling at 20 m/s accelerates to 36 m/s in 8 seconds, what is its acceleration?.

Option A. 8 m/s2.

Option B. 4 m/s2.

Option C. 2 m/s2.

Correct Answer is. 2 m/s2.

Explanation. V = u +at 36 = 20 + 8a 36-20 = 8a 16/8 = a.

Question Number. 19. A body dropped from 10 m will hit the ground in.

Option A. 2 seconds.

Option B. 0.2 seconds.

Option C. 1.41 second.

Correct Answer is. 1.41 second.

Explanation. s = ut + 1/2at2. Take s = 10, u = 0, a = g = 10. Calculate t. (Remember that 0 * t = 0).

Question Number. 20. What is the rate of gravity?.

Option A. 12.7 m/s2.

Option B. 0.981 m/s2.

Option C. 9.81 m/s2.

Correct Answer is. 9.81 m/s2.

Explanation. Gravity = 9.81 m/s2.

Question Number. 21. An object travels 18 km in 1 minute 30 seconds. What is its average speed?.

Option A. 200 m/s.

Option B. 270 m/s.

Option C. 100 ms.

Correct Answer is. 200 m/s.

Explanation. Average speed = distance/time = 18000 metres / 90 seconds = 200 m/s.

Question Number. 22. 100 m is approximately.

Option A. 220 yards.

Option B. 109 yards.

Option C. 66 yards.

Correct Answer is. 109 yards.

Explanation. m = 3.3 ft. 100 m = 330 ft. 3 ft = 1 yd so 330/3 = 110 yards.

Question Number. 23. A car moves over a distance of 5 miles at steady speed in 10 minutes. What is the speed?.

Option A. 30 mph.

Option B. 15 mph.

Option C. 60 mph.

Correct Answer is. 30 mph.

Explanation. in 10 mins, 10 miles in 20 mins, 15 miles in 30 mins, 30 miles in 1 hr.

Question Number. 24. A spaceship travels a distance of 480,000 miles in 2 days. What is its speed?.

Option A. 48,000 mph.

Option B. 36,000 mph.

Option C. 10,000 mph.

Correct Answer is. 10,000 mph.

Explanation. 480,000/48 = 10,000 MPH.

Option A. 3270 N.

Option B. 305.8 N.

Option C. 3000 N.

Correct Answer is. 305.8 N.

Explanation. F = ma F = 1000/9.81 * 3 F = 305.8 N (The 'divide by' 9.81 is necessary to convert the 1000 N into a mass (in kg)).

Question Number. 2. A time period of 10 microseconds is equal to a frequency of.

Option A. 100 kHz.

Option B. 10 kHz.

Option C. 1 Mhz.

Correct Answer is. 100 kHz.

Explanation. Frequency = 1/time period. 1/0.00001 = 100,000 = 100 kHz.

Question Number. 3. The SI unit of acceleration is the.

Option A. metre per second squared (m/s2).

Option B. metre per second (m/s).

Option C. square metre (m2).

Correct Answer is. metre per second squared (m/s2).

Explanation. NIL.

Question Number. 4. If a body starts at rest and reaches 84 m/s in 3 seconds, its acceleration is.

Option A. 28 m/s2.

Option B. 14 m/s2.

Option C. 252 m/s2.

Correct Answer is. 28 m/s2.

Explanation. Acceleration = change in speed / time.

Question Number. 5. The SI unit of velocity is the.

Option A. metre per second squared (m/s2).

Option B. metre per second (m/s).

Option C. metre (m).

Correct Answer is. metre per second (m/s).

Explanation. NIL.

Question Number. 6. An aircraft flies 1350 nmiles in 2h 15mins. What is the average speed?.

Option A. 600 nmiles/hour.

Option B. 600 miles/hour.

Option C. 150 nmiles/hour.

Correct Answer is. 600 nmiles/hour.

Explanation. Average speed = distance/time = 1350/2.25 = 600 nm/h.

Question Number. 7. A spring extends 7 cm to the ground and back again 20 times a minute. What is the period?.

Option A. 7 cm.

Option B. 3 seconds.

Option C. 1/3 cycle.

Correct Answer is. 3 seconds.

Explanation. Frequency = 20/60 = 1/3 Hz. Time period = 1/f = 3 seconds.

Question Number. 8. A cyclist goes from rest to 50 m/s in 5 seconds. What is the average acceleration?.

Option A. 10 m/s2.

Option B. 12 m/s2.

Option C. 8 m/s2.

Correct Answer is. 10 m/s2.

Explanation. Acceleration = change in speed / time.

Question Number. 9. What is the period of a frequency of 4 Hz?.

Option A. 8 seconds.

Option B. 0.25 seconds.

Option C. 4 seconds.

Correct Answer is. 0.25 seconds.

Explanation. Period = 1/f.

Question Number. 10. A dot rotates around the circumference of a circle. If the vertical position of this dot is plotted on a graph with respect to time the result will be.

Option A. a linear motion.

Option B. a transverse waveform.

Option C. a sinusoidal waveform.

Correct Answer is. a sinusoidal waveform.

Explanation. This is why an AC generator produces a sine wave frequency.

Question Number. 11. A freely falling body, falling from a height of 2km, and assuming g = 10m/s2, will strike the ground in a time of.

Option A. 400s.

Option B. 80s.

Option C. 20s.

Correct Answer is. 20s.

Explanation. From the equations of motion s = ut + 1/2at2. If it starts at rest u (and hence ut) is zero. Use s = 2000 m, plug in the numbers and transpose for t.

Question Number. 12. What is the angular velocity of a shaft rotating at 300rpm in radians/second?.

Option A. 10π radians/second.

Option B. 2π radians/second.

Option C. 5π radians/second.

Correct Answer is. 10π radians/second.

Explanation. velocity = 2π(RPM)/60 = 2π * 300/60 = 10π radians/second.

Question Number. 13. The force that acts on a body to cause it to rotate in a circular path is called the.

Option A. centripetal force.

Option B. centrifugal force.

Option C. inertia force.

Correct Answer is. centripetal force.

Explanation. Centripetal' force is the force pulling the rotating object towards the centre of rotation. 'Centrifugal' force is the equal and opposite reaction.

Question Number. 14. An aircraft of 2 metric tonnes uses 800 kilojoules kinetic energy to make an emergency stop. Its brakes apply a force of 10 kiloNewtons. What distance does it travel before it comes to a stop?.

Option A. 40m.

Option B. 800m.

Option C. 80m.

Correct Answer is. 80m.

Explanation. Energy = Force * Distance. 800,000J = 10,000N x Distance. Distance = ??.

Question Number. 15. A body rotating at an angular velocity of 5 radians/sec, with a radius of 5 metres has a speed of.

Option A. 5π metres per second.

Option B. 5 metres per second.

Option C. 25 metres per second.

Correct Answer is. 25 metres per second.

Explanation. velocity = Radius * Omega (Omega = radians/sec). V = 5 * 5 = 25 m/s.

Question Number. 16. A mass of 400 kg moves 27metres, with a force of 54N, what is the work produced?.

Option A. 1458 J.

Option B. 583.2 KJ.

Option C. 10.1 KJ.

Correct Answer is. 1458 J.

Explanation. Work = Force x Distance = 54 * 27 = 1458 J. It is not moving under gravity so the 400 kg is a red herring.

Question Number. 17. A mass on a spring nearly hits the ground 20 times a minute, its frequency is.

Option A. 3 cycles per second.

Option B. 1/3 cycle per second.

Option C. 20 cycles per second.

Correct Answer is. 1/3 cycle per second.

Explanation. cycles per minute = 20/60 cycles per second = 2/6 = 1/3 cycle per second.

Question Number. 18. A body travelling at 20 m/s accelerates to 36 m/s in 8 seconds, what is its acceleration?.

Option A. 8 m/s2.

Option B. 4 m/s2.

Option C. 2 m/s2.

Correct Answer is. 2 m/s2.

Explanation. V = u +at 36 = 20 + 8a 36-20 = 8a 16/8 = a.

Question Number. 19. A body dropped from 10 m will hit the ground in.

Option A. 2 seconds.

Option B. 0.2 seconds.

Option C. 1.41 second.

Correct Answer is. 1.41 second.

Explanation. s = ut + 1/2at2. Take s = 10, u = 0, a = g = 10. Calculate t. (Remember that 0 * t = 0).

Question Number. 20. What is the rate of gravity?.

Option A. 12.7 m/s2.

Option B. 0.981 m/s2.

Option C. 9.81 m/s2.

Correct Answer is. 9.81 m/s2.

Explanation. Gravity = 9.81 m/s2.

Question Number. 21. An object travels 18 km in 1 minute 30 seconds. What is its average speed?.

Option A. 200 m/s.

Option B. 270 m/s.

Option C. 100 ms.

Correct Answer is. 200 m/s.

Explanation. Average speed = distance/time = 18000 metres / 90 seconds = 200 m/s.

Question Number. 22. 100 m is approximately.

Option A. 220 yards.

Option B. 109 yards.

Option C. 66 yards.

Correct Answer is. 109 yards.

Explanation. m = 3.3 ft. 100 m = 330 ft. 3 ft = 1 yd so 330/3 = 110 yards.

Question Number. 23. A car moves over a distance of 5 miles at steady speed in 10 minutes. What is the speed?.

Option A. 30 mph.

Option B. 15 mph.

Option C. 60 mph.

Correct Answer is. 30 mph.

Explanation. in 10 mins, 10 miles in 20 mins, 15 miles in 30 mins, 30 miles in 1 hr.

Question Number. 24. A spaceship travels a distance of 480,000 miles in 2 days. What is its speed?.

Option A. 48,000 mph.

Option B. 36,000 mph.

Option C. 10,000 mph.

Correct Answer is. 10,000 mph.

Explanation. 480,000/48 = 10,000 MPH.

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