2. A nonzero net force acts on an object. Which of the following quantities could be constant? Explain. A. the object's kinetic energy B. the object's velocity C. the object's momentum D. all of the above E. None of the above

4. A boy throws a softball of 0.25 kg straight up into the air. It reaches a maximum altitude of 15 m and then returns to the boy's hand. Calculate the velocity of the ball when it returns to the boy's hand. (Hint: Use the principle of the Conservation of Energy)

7. According to a seated woman, a 67.7-kg man runs with his 32.4-kg dog toward a 20.2- kg child who is running toward the man. The man and dog's speed is 3.50 km/h, and the child's speed is 1.25 km/h. 1. According to the woman, what is the kinetic energy of the man-dog-child system? ( Ans: 48.5 J ) 2. According to the man, what is the kinetic energy of the man-dog-child system? ( Ans: 17.6 J )

As shown on the right two identical objects have the same mass. They are moving with the same speed but one is going due North and the other is going due East. Which of the following statements is completely correct? North a. East m m V Select one: They both have the same kinetic energies and the same momentum. b. They have different kinetic energies and they have different momentum. OC. They have the same kinetic energies, but they have different momentum. Od. They have different kinetic energies, but they have the same momentum.

Question 1

Please please answer both questions. I will really really upvote. Thanks

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A 1,500-kg car and a 3,000-kg SUV truck have the same linear momentum. Which of them has more kinetic energy? O a. O b. O C. Od. Both have the same kinetic energy The SUV truck More information is needed to determine which has more kinetic energy. The car

An empty freight car with a mass of 10,000 kg rolls at 5 m/s along a level track and collides with a loaded car with a mass of 20,000 kg, standing at rest with brakes released. Friction can be neglected. If the cars couple together, find their speed after the collision. a. Find the decrease in kinetic energy as a result of the collision. b. With what speed should the loaded car be rolling towards the empty car for both to be brought to rest by the collision? Show the figure/fbd, given and formula used.

QUESTION 8 Your mass is 94.1 kg, and the sled s mass is 20.1 kg. You start at rest, and then you jump off the sled, after which the empty sled is traveling at a speed of 3.45 m/s. What will be your speed on the ice after jumping off?   A 1.04 m/s   B 0.89 m/s   C 0.74 m/s   D 0.37 m/s