23. A snowmobile pulls a trailer with a force of 450 N while moving at a constant velocity of 15 m/s. How much work is done by the snowmobile in 28 s?

Transcription

1 Physics 04 Unit Review (June 013) 1. Which represents the rate of work done? (A) efficiency (B) force (C) power (D) work. In which situation is work done on a box? (A) The box is at rest on a table. (B) The box is held by a person who walks forward. (C) The box is pulled horizontally across a table. (D) The box is pushed and does not move. 3. A snowmobile pulls a trailer with a force of 450 N while moving at a constant velocity of 15 m/s. How much work is done by the snowmobile in 8 s? (A) 40 J (C) J (B) 40 J (D) J 4. What is the power required by an engine lifting a 75 kg mass m vertically in 30 seconds? (A) 55 W (C) W (B) 540 W (D) W 5. A block is moved a horizontal distance of 3.5 m. How much work is done on the block by a 550 N force applied at an angle of 35 o? (A) 150 J (B) 1100 J (C) 1600 J (D) 1900 J 6. What is the kinetic energy of a 0.0 kg ball travelling 7.8 m/s? (A) 0.78 J (C) 6.1 J (B) 1.6 J (D) 1 J 7. What is the SI unit for a spring constant? (A) J (B) N (C) (D) N/m 8. A stationary cart rolls down the ramp and reaches a speed of 4.0 m/s at the bottom. What is the speed of the cart at Point A? (A) 1.4 m/s (B).0 m/s (C).8 m/s (D) 4.0 m/s 9. A car at ground level has a kinetic energy of J at point A. What is the total mechanical energy of the car at point B? (A) 0 J (B) J (C) J (D) J

2 (June 011) What type of potential energy results from the bending, stretching, or compressing of matter? (A) chemical (C) gravitational (B) elastic (D) nuclear. Which factor affects the amount of work done on an object which is being pulled across a horizontal, frictionless surface? (A) displacement (C) speed (B) mass (D) time 3. How will the energy of an object change as it falls? Kinetic Energy Gravitational Potential Energy (A) Decreases Decreases (B) Decreases Increases (C) Increases Decreases (D) Increases Increases 4. In which situation is the most work being done by the force, F? (A) (C) (B) (D) 5. How much power is generated in lifting a 55 kg block 3.5 m in a time of 3. s? (A) 36 W (C) 590 W (B) 490 W (D) 1900 W 6. A force of 6.5 N is exerted upon an object causing it to move at 0.80 m/s for 9.0 s. How much work is done on the object? (A) 0.58 J (C) 47 J (B) 1.1 J (D) 73 J 7. Two balls with the same mass are placed on springs with the same spring constant. If spring B is compressed twice as much as spring A, how will the speed of ball B compare with the speed of ball A when they leave the springs? (A) 1/4 times as large (B) 1/ times as large (C) times as large (D) 4 times as large 8. How much work is done by a N force applied at an angle of 3, while moving the block a distance of.0 m? (A) J (B) J (C) J (D) J 9. What is the speed of a.9 kg object that has 16 J of kinetic energy? (A) 1.6 m/s (C) 3.3 m/s (B).7 m/s (D) 5.5 m/s

3 (June 010) 1. A teacher has twice the mass of a student. If they both run up the same flight of stairs in the same amount of time, which statement is true? (A) The student generated greater power. (C) The teacher did less work. (B) The student was faster. (D) The teacher generated greater power.. If a motor is 80% efficient, which statement regarding energy is true? (A) input > output (C) input = output (B) input < output (D) input = zero 3. A book is on top of a book shelf. Which type of energy does the book have with respect to the floor? (A) chemical (C) gravitational (B) elastic (D) kinetic 4. A 65 kg girl climbs a 4.0m ladder in 5.0 s. How much power does she generate? (A) 5 W (C) W (B) 510 W (D) W 5. A bungee cord has a spring constant of 11 N/m. How far will it stretch if a 50.0 kg mass is hung from it? (A) 0.9 m (C).4 m (B) m (D) 4.38 m 6. A truck pulls a trailer with a forward force of 3500 N while moving at a constant velocity of m/s. How much work does the truck do in 36 s? (A) J (C) J (B) J (D) J 7. What is the kinetic energy of a kg tennis ball travelling at 55 m/s? (A) 1.7 J (C) 91 J (B) 3.3 (D) 180 J 8. Object A has half the mass and four times the speed as Object B. How does the kinetic energy of Object A compare to the kinetic energy of Object B? (A) A has times the energy of B. (C) A has 8 times the energy of B. (B) A has 4 times the energy of B. (D) A has 16 times the energy of B. 9. A block on a spring demonstrates simple harmonic motion by bobbing up and down. Which statement about the block s energy is true as it travels from position X 0 to X max? (A) Elastic potential energy is constant. (B) Gravitational potential energy is constant. (C) Kinetic energy is constant. (D) Total mechanical energy is constant

4 (June 013) (a) A kg car accelerates from 5.0 m/s and covers a distance of 47 m. The force produced by the engine is 9700 N. (i) Calculate the work done by the engine. (1%) (ii) Calculate the final speed of the car. (%) 43. (b) A.5 kg ball travels at a constant speed of 6.0 m/s before colliding with a spring with a spring constant of 80 N/m. Calculate how much the spring compresses before the ball stops. (3%) (June 011) 43. (a) An 80.0 kg stuntman falls from the top of a 70.0 m high building. (i) What is the total mechanical energy of the stuntman when on top of the building? (%) (ii) What is the stuntman s speed at a height of 30.0 m above the ground? (%) 43. (b) A 45 kg child bounces on a trampoline with a spring constant of N/m. If the trampoline is compressed 0.35 m and is 75% efficient, how high will the child bounce above the uncompressed trampoline? (3%) 4. (c) A javelin with a mass of 1. kg is thrown at a speed of 8 m/s. How much force does the athlete exert over a throwing distance of 1.5 m? (%)

5 (June 010) 43. (a)a 5.00 x 10 kg roller coaster travels at a speed of 15.0 m/s when at a height of 5.00 m above the ground (assume mechanical energy is conserved). i) Calculate the kinetic energy at 5.00 m. (1%) ii) Calculate the gravitational potential energy at 5.00 m. (1%) iii) Calculate the speed of the roller coaster when it is at a height of 10.0 m. (3%) 43. (b) A 605 kg race car accelerates from 0.0 m/s to 60.0 m/s. i) Calculate the work done during the acceleration. (3%) ii) If the car generates 58 kw of power, calculate the time it took to accelerate. (%) 43. (c) A horizontal spring having a spring constant of 40.0 N/m undergoes simple harmonic motion when a 1.0 kg mass stretches it 0.0 cm from its rest position. Calculate the speed of the mass when it is 5.00 cm from the rest position. (4%) (June 009) 43. a) A force of 85 N is applied to a lawn mower at an angle of 60.0 above the horizontal. 0 Calculate the distance the mower must be pushed to do J of work. (3%)

6 3 43. b) A.0 10 W winch is used to raise a 100 kg car vertically from a ditch. Calculate how high the car is raised if the winch operates for 7 s. (3%) 43. c) A kg cart is released from rest at the top of a ramp and allowed to roll down the ramp and across a level floor as shown. Data are collected and plotted on the velocity vs. time graph below. Calculate the original height, h, of the ramp. (4%)