EmSAT Achieve (UAE) · Physics

Mechanics and Thermodynamics

26 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 26 questions

  1. A car accelerates uniformly from rest to a speed of 24 m/s over a distance of 72 m. What is the magnitude of the car's acceleration?
  2. A 5.0 kg crate is pushed across a horizontal floor by a horizontal force of 35 N. If the coefficient of kinetic friction between the crate and the floor is 0.30 (take g = 9.8 m/s²), what is the crate'…
  3. A stone is thrown horizontally from the top of a 45 m tall cliff with an initial speed of 15 m/s. Neglecting air resistance and using g = 10 m/s², how far from the base of the cliff does the stone lan…
  4. A 2.0 kg ball traveling at 6.0 m/s collides head-on with a stationary 4.0 kg ball. If the collision is perfectly inelastic and they stick together, what is their final common speed?
  5. A uniform beam of length 4.0 m and weight 200 N is supported horizontally at both ends. If a 600 N weight is placed 1.0 m from the left support, what upward force is exerted by the left support?
  6. A 1000 kg roller coaster car starts from rest at the top of an 80 m tall hill. Neglecting friction and taking g = 9.8 m/s², what is the kinetic energy of the car at a height of 30 m above the ground?
  7. A satellite orbits the Earth in a circular path of radius R with orbital speed v. If the orbital radius is quadrupled to 4R, what is the new orbital speed?
  8. An ideal gas undergoes an isothermal expansion at temperature T. Which statement regarding this process is true?
  9. A heat engine absorbs 1500 J of heat from a high-temperature reservoir and expels 900 J to a cold reservoir during each cycle. What is its thermal efficiency?
  10. How much heat energy is required to raise the temperature of 0.50 kg of liquid water from 20°C to 80°C? (Specific heat capacity of water = 4186 J/(kg·°C))
  11. A 0.40 kg object attached to an ideal horizontal spring with force constant k = 160 N/m undergoes simple harmonic motion. What is the angular frequency ω of the oscillations?
  12. A Carnot engine operates between a hot reservoir at 600 K and a cold reservoir at 300 K. If it absorbs 2400 J of heat from the hot reservoir, what is the maximum mechanical work it can produce?
  13. A constant force of 25 N acts on a 5.0 kg body for 4.0 seconds. What is the total change in momentum experienced by the body?
  14. A solid cylinder and a thin hoop of equal mass and equal radius roll without slipping down the same inclined plane from rest. Which object reaches the bottom first?
  15. An object moves along a circular path of radius 5.0 m at a constant speed of 10 m/s. What is the magnitude of its centripetal acceleration?
  16. A 1500 kg vehicle traveling at 20 m/s is brought to a complete stop by braking over a distance of 50 m. What average braking force was applied?
  17. Under standard atmospheric conditions, 2.0 moles of an ideal gas are kept at 300 K in a 0.050 m³ container. What is the approximate gas pressure? (Take R = 8.31 J/(mol·K))
  18. A 0.50 kg pendulum bob is released from a height of 0.80 m above its lowest point. Taking g = 9.8 m/s² and neglecting friction, what is its speed at the lowest point?
  19. Which of the following physical quantities is an intensive thermodynamic property?
  20. A diver stands at the edge of a 10 m diving board. If the board's deflection is doubled under a heavier load, how does the elastic potential energy stored in the board change?
  21. A hydraulic lift has an input piston of radius 2.0 cm and an output piston of radius 20 cm. What force must be exerted on the input piston to balance a 10,000 N load on the output piston?
  22. An insulated container holds 0.20 kg of water at 20°C. If 0.10 kg of copper at 100°C is added, what is the final equilibrium temperature? (c_water = 4186 J/(kg·K), c_copper = 386 J/(kg·K))
  23. What is the escape velocity from the surface of a spherical planet having twice the mass and twice the radius of Earth? (v_e,Earth ≈ 11.2 km/s)
  24. A wheel initially rotating at 12 rad/s accelerates uniformly at 3.0 rad/s² for 4.0 seconds. Through what total angular displacement does it turn during this time?
  25. How much work is required to stretch a spring with spring constant k = 250 N/m from an extension of 0.10 m to 0.30 m?
  26. According to the second law of thermodynamics, what occurs to the total entropy of an isolated system during an irreversible spontaneous process?

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