Download 1. Find the weight of a 2.3 kg bowling ball on Earth.

Friction Questions 1.
Find the weight of a 2.3 kg bowling ball on Earth. 2.
You have a weight of 652.58 N[down] while standing on a spring scale on Earth near the equator. a)
Calculate your mass. b)
Determine your weight on Earth near the North Pole. c)
Determine your weight on the International Space Station. Why would this value be impossible to verify experimentally? 3.
The lunar roving vehicle (LRV) pictured here has a mass of 209 kg regardless of where it is, but its weight is much less on the surface of the Moon than on Earth. Calculate the LRV’s weight on Earth and on the Moon. 4.
A 1.00 kg mass is used to determine the acceleration due to gravity of a distant, city‐sized asteroid. a)
Calculate the acceleration due to gravity if the mass has a weight of [down] on the surface of the asteroid. 5.
A friend pushes a 600 g textbook along a lab bench at constant velocity with 3.50 N of force. a)
Determine the normal force supporting the textbook. b)
Calculate the force of friction and coefficient of friction between the book and the bench. c)
Which coefficient of friction have you found, µS or µK ? 6.
A 125 kg crate full of produce is to be slid across a barn floor. a)
Calculate the normal force supporting the crate. b)
Calculate the minimum force required to start the crate moving if the coefficient of static friction between the crate and the floor is 0.430. c)
Calculate the minimum force required to start the crate moving if half of the mass is removed from the crate before attempting to slide it. 7.
Avalanches often result when the top layer of a snow pack behaves like a piece of glass, and begins sliding over the underneath layer. a)
Calculate the force of static friction between two layers of horizontal ice on the top of Mount Everest, if the top layer has a mass of (Refer to Table 4.5 for the coefficient of friction.) 8.
Assume that, in the “Try This” experiment on page 148, you discovered that you had to push the book against the wall with a force of 63 N in order to prevent it from falling. Assume the mass of the book to be 2.2 kg. a)
What is the coefficient of static friction between the book and the wall? (Hint: Be careful to correctly identify the source of the normal force and the role of the frictional force in this situation.) Newton’s Second Law 9.
A 4.0 kg object experiences a net force of 2.2 N [E]. Calculate the acceleration of the object. 10. A 6.0 kg object experiences an applied force of 4.4 N [E] and an opposing frictional force of 1.2 N [W]. a) Calculate the acceleration of the object. 11. A 15 kg object experiences an applied force of 5.5 N [N] and an opposing frictional force of 2.5 N [S]. If the object starts from rest, how far will it have travelled after 4.0 s? 12. A 45 kg student rides his 4.0 kg bicycle, exerting an applied force of 325 N [E].
a) Calculate the acceleration of the cyclist if frictional resistance sums to 50.0 N [W].
b) How far will the student have travelled if he started with a velocity of at 3.0 m/s [E] and accelerated for 8.0 s? 13. A stretched elastic exerts a force of 2.5 N [E] on a wheeled cart, causing it to accelerate at Calculate the mass of the cart, ignoring frictional effects. 14.
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The driver of a car travelling 45 km/h [W] on a slippery road applies the brakes, skidding to a stop in 35 m. Determine the coefficient of friction between the road and the car tires. A swimmer is propelled directly north by a 17. A train car is pulled along the tracks by a force of 35.0 N. Moving water exerts a second force of 1500 N from a pickup truck driving force of 20 N [E]. Use both a scale diagram beside the tracks. The rope connecting the and a mathematical solution to determine truck and the train car makes an angle of 15˚ the net force acting on the swimmer to the direction of travel. Find the resultant force acting on each object pictured. Obtain values by measuring the vectors. A train car is pulled along the tracks by a force of 1500 N from a pickup truck driving beside the tracks. The rope connecting the truck and the train car makes an angle of 15° to the direction of travel. a)
Find the component of the pulling force in the direction of travel. b)
Find the component of the pulling force perpendicular to the direction of travel. A student pushes a 25 kg lawn mower with a force of 150 N. The handle makes an angle of 35° to the horizontal. a)
Find the vertical and horizontal components of the applied force. b)
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Calculate the normal force supporting the lawn mower while it is being pushed. Calculate the net force propelling the mower if a frictional force of 85 N exists. 19. Calculate the horizontal acceleration of the lawn mower. (Remember: Only part of the FAPPLIED is parallel to the direction of horizontal acceleration.) Section Review Questions 1.
State Newton’s first law and give two examples. 2.
State Newton’s second law and give two examples. 3.
State Newton’s third law and give two examples. 4.
By how much will an object’s acceleration change if a)
the force is doubled? b)
the mass of the object is halved? c)
the mass is doubled and the force is halved? 5.
State the equal‐and‐opposite force pairs in each of the following situations: a)
kicking a soccer ball b)
a pencil resting on a desk c)
stretching an elastic band 6.
A block of pure gold is perfectly balanced by a 2.0 kg lead mass. Describe what would happen to this setup if it was placed on the Moon. Table 4.5 Coefficients of Friction Numerical Answers to Practice Problems 1.
23 N 2.
(a) 66.722 kg (b) 656.03 N (c) 605.81 N 3.
WEARTH = 2.05 x 103 N, WMOON = 3.43 x 102 N 4.
3.25 x 10‐2 m/s2 5.
(a) 5.89 N (b) 3.50 N; 0.595 (c) µK 6.
(a) 1.23 X 103 N (b) 527 N (c) 264 N 7.
1.95 x 102 N 8.
0.34 9.
0.55 m/s2 [E] 10. 0.53 m/s2 [E] 11. 1.6 m [N] 12. (a) 5.6 m/s2 (b) 2.0 x 102 m [E] 13. 1.7 kg 14. 0.23 15. 40 N [N30°E] 16. (a) 43 N [E] (b) 7.4 N [N] (c) 15 N [E] (d) 15 N [W28°S] 17. (a) 1.4 x 103 N (b) 3.9 x 102 N 18. (a) FX = 120 N, FY = ‐86 N, (b) 3.3 x 102 N (c) 38 N in direction 2.3° below the horizontal (d) 1.5 m/s2