1. If a0.6kg object hanging from a spring stretches it by0.45m, then by how much will the spring be stretched (in m) if a1.2kgobject is suspended from it?

____m

2. The mass is pulled to the right a distance of 0.2 m and released. Rank the following spring-mass combinations according to their oscillation periods from longest to shortest. If any combinations have the same period, give them the same rank. You should assume that there is no friction between the mass and the horizontal surface. (Use only ">" or "=" symbols. Do not include any parentheses around the letters or symbols.)

1. k = 0.8 N/m; m = 0.25 kg
2. k = 0.8 N/m; m = 0.50 kg
3. k = 0.8 N/m; m = 1.00 kg
4. k = 1.6 N/m; m = 0.25 kg
5. k = 1.6 N/m; m = 0.50 kg

3. Suppose an airline allows a maximum of 39 kg for each suitcase a passenger brings along.

(a)What is the weight in newtons of a 39 kg suitcase? N

(b)What is the weight in pounds? lb

4. The mass of a subway car and passengers is 35,300 kg. If its acceleration as it leaves a station is 0.8 m/s², what is the net force (in N) acting on it? (Enter the magnitude.)

N

5. In an experiment performed in a space station, a force of 42 N causes an object to have an acceleration equal to 5 m/s². What is the object's mass? kg

6. A person stands on a scale inside an elevator at rest . The scale readsW=717N.(a) What is the person's mass? kg (b) The elevator accelerates upward momentarily at the rate ofa=4m/s².What does the scale read then? N (c) The elevator then moves with a steady speed of4m/s. What does the scale read now?

7. On aircraft carriers, catapults are used to accelerate jet aircraft to flight speeds in a short distance. One such catapult takes a 18,500-kg jet from 0 to 68 m/s in 2.9 s. (Assume the catapult acts in the positive horizontal direction. Indicate the direction with the sign of your answer where appropriate.)(a) What is the acceleration of the jet in m/s²? m/s² What is the acceleration of the jet in g's? g (b) How far does the jet travel while it is accelerating? m (c) How large is the force that the catapult must exert on the jet?

8. On a highway curve with radius 40 m, the maximum force of static friction (centripetal force) that can act on a 1,323-kg car going around the curve is 9,327 N. What speed limit should be posted for the curve so that cars can negotiate it safely? m/s

9.A space probe is launched from Earth headed for deep space. At a distance of 10,000 miles from Earth's center, the gravitational force on it is 366 lb. What is the size of the force when it is at each of the following distances from Earth's center?(a) 20,000 miles lb (b) 30,000 miles lb (c) 100,000 miles lb

10. The Kingda Ka roller coaster in New Jersey is the world's tallest ride of its kind. As the passenger cars are launched from rest at the start, they are accelerated uniformly to a speed of 57 m/s (128 mph) in just 3.5 s. (Assume the cars are launched in the positive horizontal direction. Indicate the direction with the sign of your answer where appropriate.)(a) What is the acceleration experienced by passengers on this ride in m/s²? m/s² What is the acceleration experienced by passengers on this ride in g's? g (b) If a certain passenger has a mass of 72 kg, what is the force in newtons that acts on him during the launch phase of this ride? N What is the force in pounds that acts on him during the launch phase of this ride? lb

11. A jet aircraft with a mass of4,325kg has an engine that exerts a force (thrust) equal to59,900N.(a) What is the jet's acceleration when it takes off? (Give the magnitude.) m/s² (b)What is the jet's speed after it accelerates for5s? (Assume it starts from rest.) m/s (c) How far does the jet travel during the5s? m

12. A race car rounds a curve at 52 m/s. The radius of the curve is 450 m, and the car's mass is 630 kg. (Assume the car's speed remains constant. Take the radially inward direction to be positive. Indicate the direction with the sign of your answer.)(a) What is the car's (centripetal) acceleration? m/s² What is it in g's? g (b) What is the centripetal force acting on the car? N

13. A centripetal force of 155 N acts on a 1,400-kg satellite moving with a speed of 5,400 m/s in a circular orbit around a planet. What is the radius of its orbit? m