Class 9 Practice Level 2 – Work and Energy set – 2 Leave a Comment / By anushka kumari / July 10, 2024 Class 9 Practice Level 2 – Work and Energy set – 2 Total questions: 25 1. A force of 80 N is applied to move a box 5 meters across a floor. If the force is applied at an angle of 45 degrees to the horizontal, what is the work done by the force? Topic: Work 200 J 283 J 400 J 566 J None 2. A 1200 kg car is moving with a speed of 15 m/s. What is its kinetic energy? Topic: Energy 135,000 J 180,000 J 225,000 J 270,000 J None 3. If a motor raises 200 liters of water per minute to a height of 15 meters, what is the power of the motor? (Take g=10 m/$ \displaystyle {{s}^{{2}}}$; 1 liter of water = 1 kg) Topic: Power 500 W 750 W 1000 W 1250 W None 4. An object is lifted vertically 8 meters by a force of 120 N. What is the work done against gravity? Topic: Work 480 J 720 J 960 J 1200 J None 5. A pendulum bob of mass 0.8 kg is raised to a height of 0.4 meters. What is its potential energy at this height?$ \displaystyle \left( {\text{Take }g=10m/{{s}^{2}}} \right)$ Topic: Energy 1.6 J 2.4 J 3.2 J 4.8 J None 6. A machine does 6000 joules of work in 30 seconds. What is its power output? Topic: Power 150 W 200 W 250 W 300 W None 7. A person pulls a cart with a force of 60 N over a distance of 15 meters in 10 seconds. What is the power exerted by the person? Topic: Work 60 W 90 W 120 W 150 W None 8. A ball of mass 0.5 kg is moving with a velocity of 8 m/s. What is its kinetic energy? Topic: Energy 8 J 16 J 20 J 32 J None 9. If a motor does 4500 J of work in 15 seconds, what is its power output? Topic: Power 200 W 250 W 300 W 400 W None 10. A crane lifts a load of 750 kg to a height of 12 meters. How much work is done?$ \displaystyle \left( {\text{Take }g=10m/{{s}^{2}}} \right)$ Topic: Work 7500 J 9000 J 75,000 J 90,000 J None 11. A spring with a spring constant of 300 N/m is compressed by 0.1 meters. What is the potential energy stored in the spring? Topic: Energy 1.5 J 3 J 4.5 J 6 J None 12. A person does 500 J of work by lifting a box in 8 seconds. What is the power developed by the person? Topic: Power 50 W 62.5 W 75 W 87.5 W None 13. A force of 40 N is applied to move a box 6 meters. The force is applied at an angle of 30 degrees to the direction of motion. What is the work done? Topic: Energy 100 J 120 J 150 J 200 J None 14. A person pulls a sled with a force of 50 N at an angle of 60 degrees to the horizontal. If the sled is pulled a distance of 6 meters, what is the work done? Topic: Work 150 J 180 J 200 J 240 J None 15. A 4 kg object is moving with a velocity of 12 m/s. What is its kinetic energy? Topic: Energy 72 J 144 J 216 J 288 J None 16. A person does 720 J of work in 3 minutes. What is the power developed by the person in watts? Topic: Power 2 W 3 W 4 W 5 W None 17. An electric motor lifts a 12 kg object to a height of 10 meters in 4 seconds. What is the power output of the motor? Topic: Work 250 W 300 W 400 W 500 W None 18. A stone of mass 0.4 kg is thrown vertically upward with an initial velocity of 20 m/s. What is its kinetic energy at the highest point? Topic: Energy 0 J 40 J 80 J 160 J None 19. An electric pump does 12,000 J of work in pumping water in 80 seconds. What is the power of the pump? Topic: Power 100 W 120 W 150 W 200 W None 20. If a person pushes a box with a force of 25 N at an angle of 45 degrees to the horizontal and moves it 8 meters, what is the work done? Topic: Work 100 J 125 J 140 J 150 J None 21. A 2 kg mass is lifted to a height of 3 meters. What is the potential energy gained by the mass?$ \displaystyle (\mathbf{Take}\text{ }\mathbf{g}=\mathbf{10}\,\mathbf{m}/\mathbf{s^2})$ Topic: Energy 20 J 30 J 50 J 60 J None 22. If an electric motor does 5400 J of work in 45 seconds, what is its power output? Topic: Power 100 W 120 W 140 W 150 W None 23. A machine does 9000 J of work in moving an object 15 meters. What is the force exerted by the machine? Topic: Work 300 N 450 N 600 N 750 N None 24. A 3 kg object is dropped from a height of 5 meters. What is its kinetic energy just before it hits the ground?$ \displaystyle (\mathbf{Take}\text{ }\mathbf{g}=\mathbf{10}\,\mathbf{m}/\mathbf{s^2})$ Topic: Energy 50 J 100 J 150 J 200 J None 25. A person pulls a sled with a force of 50 N at an angle of 60 degrees to the horizontal. If the sled is pulled a distance of 6 meters, what is the work done? Topic: Work 150 J 180 J 200 J 240 J None 1 out of 25 Time's up
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