Rita accelerates a 0.50-kg ball from rest to 8.0 m/s during the 0.14 s in which her foot is in contact with the ball. What average force does she apply to the ball during the kick?
a. 110 N
b. 22 N
c. 29 N
d. 56 N
e. 2.2 N
[Ques. 2] A cart of weight 15.0 N is accelerated across a level surface at 0.15 m/s2 . What net force acts on the wagon? (g = 9.8 m/s2)
a. 22 N
b. 0.23 N
c. 2.3 N
d. 10 N
e. 100 N
[Ques. 3] A 2 000-kg sailboat experiences an eastward force of 4 500 N by the ocean tide and a wind force against its sails with magnitude of 1 500 N directed toward the northwest (45 N of W). What is the direction of the resultant acceleration?
a. 27 N of W
b. 58 N of W
c. 27 N of E
d. 17 N of W
e. 17 N of E
[Ques. 4] A 3 000-kg sailboat experiences an eastward force of 4 500 N by the ocean tide and a wind force against its sails with magnitude of 5 800 N directed toward the northwest (45 N of W). What is the magnitude of the resultant acceleration?
a. 1.4 m/s2
b. 3.2 m/s2
c. 2.4 m/s2
d. 3.4 m/s2
e. 1.3 m/s2
[Ques. 5] If we know that a nonzero net force is acting on an object, which of the following must we assume regarding the object's condition? The object is:
a. at rest.
b. moving with a constant velocity.
c. being accelerated.
d. losing mass.
[Ques. 6] The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. What net force would be required to accelerate a 25.0-kg object at 5.80 m/s2 on the Moon?
a. 4.31 N
b. 24.2 N
c. 8.7 N
d. 145 N
e. 25.9 N
[Ques. 7] The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. An astronaut's life support backpack weighs 250 lb on Earth. What does it weigh on the Moon?
a. 1 500 lb
b. 250 lb
c. 256 lb
d. 41.7 lb
e. 244 lb
[Ques. 8] Two forces act on a 8.50-kg object. One of the forces is 14.0 N. If the object accelerates at 3.50 m/s2, what is the greatest possible magnitude of the other force?
a. 1.0 N
b. 15.8 N
c. 43.8 N
d. 26.3 N
e. 73.5 N
[Ques. 9] Two ropes are attached to a 50-kg object. The first rope applies a force of 35 N and the second, 55 N. If the two ropes are perpendicular to each other, what is the resultant acceleration of the object?
a. 1.3 m/s2
b. 35 m/s2
c. 1.8 m/s2
d. 65 m/s2
e. 0.77 m/s2
[Ques. 10] An astronaut applies a force of 450 N to an asteroid, and it accelerates at 7.0 m/s2 . What is the asteroid's mass?
a. 64 kg
b. 450 kg
c. 460 kg
d. 3 200 kg
e. 0.016 kg