PHY 101 Week 1 Individual Assignment Textbook Exercises
PHY 101 Week 1 Individual Assignment Textbook Exercises Recent
Chapter 3
20. Suppose that the three balls shown in Exercise 19 start simultaneously from the tops of the hills. Which one reaches the bottom first? Explain
22. Which is greater, an acceleration from 25 km/h to 30 km/h or one from 96 km/h to 100 km/h if both occur during the same time?
Chapter 4
14. Gravity on the surface of the Moon is only 1/6 as strong as gravity on Earth. What is the weight of a 10-kg object on the Moon and on Earth? What is its mass on each?
18. A grocery bag can withstand 300 N of force before it rips apart. How many kilograms of apples can it safely hold?
Chapter 5
14. If you exert a horizontal force of 200 N to slide a crate across a factory floor at constant velocity, how much friction is exerted by the floor on the crate? Is the force of friction equal and oppositely directed to your 200 N push? If the force of friction isn’t the reaction force to your push, what is?
Chapter 6
8. A person can survive a feet-first impact at a speed of about 12 m/s (27 mi/h) on concrete; 15 m/s (34 mi/h) on soil; and 34 m/s (76 mi/h) on water. Why the different values for different surfaces?
20. Why does a baseball catcher’s mitt have more padding than a conventional glove?
Chapter 7
14. Explain how “elastic potential energy” dramatically changed the sport of pole vaulting when flexible fiberglass poles replaced stiffer wooden poles
36. When the girl in Figure 7.16 jacks up a car, how can applying so little force produce sufficient force to raise the car?
Chapter 9
12. An apple falls because of the gravitational attraction to Earth. How does the gravitational attraction of Earth to the apple compare? (Does force change when you interchange m1 and m2 in the equation for gravity— m2m1 instead of m1m2?
22. The planet Jupiter is more than 300 times as massive as Earth, so it might seem that a body on the surface of Jupiter would weigh 300 times as much as on Earth. But it so happens that a body would scarcely weigh 3 times as much on the surface of Jupiter as it would on the surface of Earth. Can you think of an explanation for why this is so? (Hint: Let the terms in the equation for gravitationalforce guide your thinking.)