Module 5 Quizzes Flashcards
Davina accelerates a box across a smooth frictionless horizontal surface over a displacement of 18.0 m with a constant 25.0 N force angled at 23.0 degrees below the horizontal. How much work does she do on the box?
A. 176 J
B. 414 J
C. 450 J
D. 511 J
B
An object moving at 21.0 m/s has 1390 J kinetic energy. What is the object’s mass?
A. 6.30 kg
B. 66.2 kg
C. 3.15 kg
D. 33.1 kg
A
A 13 kg mass object initially has 2500 J of kinetic energy. -1200 J of net work is then done on the object by a force opposite the direction of the object’s motion. What is the final speed of the object?
A. 14 m/s
B. 24 m/s
C. 20 m/s
D. 17 m/s
A
A metalsmith at a foundry drags a hunk of steel across the horizontal foundry floor by pully on it with a 320 N force angled 28 degrees above the floor. If the kinetic friction force due to the floor is essentially constant at 280 N, what is the net work done on the hunk of steel by metalsmith and the kinetic friction over a distance of 11m?
A. 3100 J
B. 3500 J
C. 440 J
D. 28 J
D
Two children have identical spring-loaded catapults, which contain springs constant k. If Samir compresses the spring in his catapult by a distance x and Mona compresses hers by a distance 2x, how does the work they have done to compress their catapults compare?
A. Mona has done 2 times as much work as Samir.
B. Samir has done 2 times as much work as Mona.
C. They have done the same amount of work.
D. Mona has done 4 times as much work as Samir.
D.
A 1.5 kg block sliding along a frictionless horizontal surface at 2.9 m/s collides with and compresses a spring attached to a wall with a spring constant k = 390 N/m. What distance is the spring compressed from its equilibrium position?
A. 3.2 cm
B. 18 cm
C. 11 m
D. 7.3 m
B
You lift a box off the ground and then hold it at a height above your waist. Which does not describe the work or energy in this process?
A. You did positive work on the box.
B. Gravity did negative work on the box.
C. The box’s gravitational potential energy increased.
D. The box’s kinetic energy remained constant throughout the process.
D
A frictionless plane inclined at 21 degrees above the floor has a length of 3.3 m. A block starts from rest at the top of the inclined plane and slides down to the floor. What is its speed when it reaches the floor?
A. 4.8. m/s
B. 3.4 m/s
C. 5.1 m/s
D. Cannot be determined
A
Gina’s moped has an output of 6.0 horsepower (1 horsepower = 745.7 W), and its mass is 190 kg. If Gina’s mass is 50 kg, how long does it take for her to reach a speed of 8.0 m/s if she starts her moped from rest?
A. 0.92 s
B. 1.3 s
C. 2.2 s
D. 1.7 s
D
The burner in a hot air balloon adds 6400 J of heat to the balloon while the balloon expands, it does 3100 J work on the surrounding air. What is the internal change in the thermal energy of the balloon?
A. +6400 J
B. -3300 J
C. +9500 J
D. +3300 J
D
