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Transcript of Forces Newtonâ€™s Laws MC Practice Newtonâ€™s Laws MC Practice...

• Forces & Newtons Laws MC Practice Questions 1) Which of Newtons laws describes equilibrium?

a) The first, which mathematically states that F = 0. b) The second, which mathematically states that F = ma. c) The third, which mathematically states that F = -F. d) The fourth, which mathematically states that F = Gm1m2/r2. e) The fifth, which mathematically states that dx/dt = v. 2) If all of the forces acting on an object balance so that the net force is zero, then

a) the object must be at at rest b) the objects speed will increase c) the objects direction of motion can change, but not its speed d) None of the above will occur. 3) Object A, when acted upon by a force F, accelerates at a rate of 4.0 m/s/s. The same force accelerates Object B at a rate of 8.0 m/s/s. Compared to the mass of Object A, the mass of Object B is:

a) Four times as great b) Twice as great c) The same d) One-half as great e) One-fourth as great

• Forces & Newtons Laws MC Practice Questions 4) An object is supported by a spring attached to the ceiling. What are the forces acting on the object? a) The mass of the object in the downward direction and the supporting force of the spring in the upward direction b) The mass of the object in the downward direction and the supporting force of the spring in the downward direction c) The weight of the object in the upward direction and the supporting force of the spring in the downward direction d) The weight of the object in the downward direction and the supporting force of the spring in the upward direction e) The weight of the object pulling on the Earth and the downward supporting force of the spring 5) Rank the following scenarios from the greatest to the smallest acceleration:

I. Net force F applied to mass M II. Net force 2F applied to mass M III. Net force F applied to mass 2M IV. Net force 2F applied to mass 2M

a) II > I = IV > III b) I > II > III > IV c) III > IV = I > II d) IV > II > III > I e) III > I = II > IV

• Forces & Newtons Laws MC Practice Questions 6) Two forces are applied to a body initially at rest on a frictionless surface as shown below. Rank the diagrams from the largest acceleration to the least.

a) B > D > A > C b) B > A = C > D c) C > A > B > D d) C > B > A > D

• Forces & Newtons Laws MC Practice Questions 7) A body weighing 49 N is lifted by a cord as shown in the diagram below. What acceleration does the body experience?

a) 6.0 m/s2 b) 5.0 m/s2 c) 1.2 m/s2 d) 0.83 m/s2 Multi-select: For questions 38-41, two of the suggested answers will be correct. Select the two best answers, and circle both. 8) A book is resting on a table. Which of the following forces act on the book? a) The gravitational force b) The of the book on the table c) The supporting force of the table on the book d) The net downward force of air on the book e) The force of the table on the floor

• Forces & Newtons Laws MC Practice Questions 9) Consider the forces on a child standing in an elevator. When is the normal force from the elevator equal to the gravitational force? a) When the elevator moves upward at a constant speed b) When the elevator accelerates upward c) When the elevator is at rest d) When the elevator accelerates downward at a constant rate e) When the child is jumping off the floor of the elevator 10) A person standing on a horizontal floor feels two forces: the downward pull of gravity and the upward supporting force from the floor. These two forces

a) have equal magnitudes and form an action/reaction pair b) have equal magnitudes and do not form an action/reaction pair c) have unequal magnitudes and form an action/reaction pair d) have unequal magnitudes and do not form an action/reaction pair

• Forces & Newtons Laws MC Practice Questions 11) A person who weighs 800 N steps onto a scale that is on the floor of an elevator car. If the elevator accelerates upward at a rate of 5 m/s2, what will the scale read? a) 400 N b) 800 N c) 1000 N d) 1200 N 12) This position-time graph is typical of which type of motion?

a) Motion of an object with an increasing net force acting upon it. b) Motion with zero velocity. c) Motion of an object with an increasing net force acting upon it. d) Motion of an object with no net force acting upon it. e) Motion of an object with negative net force acting upon it.

• Forces & Newtons Laws MC Practice Questions 13) An objects position with time is depicted in this graph. At which time range will there be nearly no net force acting on the object?

a) 0.5 to 1.0 s b) 1.0 to 1.5 s c) 1.8 to 2.2 s d) 2.5 to 3.0 s

• Forces & Newtons Laws MC Practice Questions 14) This graph depicts the velocity of a skydiver over time during free-fall. Which of the following statements is true?

a) The net forces acting on the skydiver increase until the acceleration reaches its maximum and the velocity becomes constant. b) The net forces acting on the skydiver decrease until the acceleration reaches zero and the velocity becomes constant. c) There are no net forces acting on the skydiver. d) The net forces acting on the skydiver increase until the acceleration reaches zero and the velocity becomes constant. e) The net forces acting on the skydiver decrease until the acceleration reaches zero and the velocity becomes zero.

• Forces & Newtons Laws MC Practice Questions 15) A boy is pushing a 50 kg crate across a frictionless surface. The velocity is changing with time as shown in this graph. What is the magnitude of the force that the boy applies to the crate?

a) 5 N b) 10 N c) 15 N d) 20 N e) 25 N

• Forces & Newtons Laws MC Practice Questions 16) A 1.80 kg body experiences a force acting on it for 5.00s. The graph representing the velocity of the body vs. time is given below.

What was the magnitude of the force?

a) 5.40 N b) 3.00 N c) 1.50 N d) 0.60 N

• Forces & Newtons Laws MC Practice Questions 17) The acceleration-time graph of an objects motion is shown in this figure. At what time will the forces acting on it be balanced?

a) 0 s b) 1 s c) 2 s d) 3 s e) 4 s

• Forces & Newtons Laws MC Practice Questions 18) The acceleration of a 5 kg object over time is shown in this graph. What is the net force at 1 s?

a) -10 N b) -5 N c) -2.5 N d) 5 e) 10 N 19) Two boys push a 5 kg box on a frictionless floor. James pushes the box with a 10 N force to the right. Louis pushes the box with an 8 N force to the left. What is the magnitude and direction of the boxs acceleration? a) 0 m/s2; the box does not move b) 0.4 m/s2 to the right c) 0.4 m/s2 to the left d) 1.6 m/s2 to the right e) 1.6 m/s2 to the left

• Forces & Newtons Laws MC Practice Questions 20) Only two forces act on a 0.1 kg object. This graph depicts the magnitudes and directions of only those two forces. What is the acceleration of the object at the 2 s clock reading?

a) 0 m/s2 b) 0.2 m/s2 c) 1.0 m/s2 d) 2.0 m/s2 e) 4.0 m/s2

• Forces & Newtons Laws MC Practice Questions 21) You pull straight down on one side of a rope stretched across a pulley. Attached to the other side of the rope is a 10 kg box. How much force must you pull down on the rope to the get the box to accelerate upward at a rate of 10 m/s2?

a) 10 N b) 20 N c) 100 N d) 150 N e) 200 N

22) A 5.00 kg body is supported by a single cord that hangs from the ceiling of a room. The tension in the cord is

a) 5.00 kg b) 5.00 N c) 49.0 kg d) 49.0 N

23) A six-strand vertical pulley is used to raise a load with a mass of 1,000 kg. The tension on the pulley cables is closest to which of the following?

a) 15,000 N b) 1,000 N c) 1,600 N d) 10,000 N e) 170 N

• Forces & Newtons Laws MC Practice Questions 24) A person stands on a bathroom scale in an elevator moving downward with an acceleration of -2.00 m/s2. The bathroom scale will read a) the true weight of the person b) a weight larger than the true weight of the person c) a weight smaller than the true weight of the person d) a fractional change in the true weight, but since the true weight is not given, there is no way to determine it 25) A soldier fires a musket with a barrel that is 1 m in length. The gases from the exploding gunpowder exert a net force of 50 N on a 0.010 kg bullet as it travels through the musket barrel. What is the bullets velocity as it leaves the musket barrel? a) 10 m/s b) 100 m/s c) 1,000 m/s d) 10,000 m/s e) 100,000 m/s

• Forces & Newtons Laws MC Practice Questions 26) A 3 kg mass is moving at 6 m/s is brought to rest in 2 s. The magnitude of the force acting on the mass it

a) 18 N b) 9 N c) 6 N d) 12 N e) 36 N 27) A car with a mass of 1,000 kg travels at 30 m/s. The driver applies his brakes for a uniform deceleration and comes to a complete stop in 60 m. Assuming that the forward motion is positive, what is the magnitude and direction of the net force acting on the car? a) 7,500 N b) 5,000 N c) -1,000 N d) -5,000 N e) -7,500 N

• Forces & Newtons Laws MC Practice Questions 28) A bowler applies a constant net force of 100 N on a 5 kg bowling ball over a time period of 1.5 s before he releases the ball. The ball starts from rest. What is its final velocity? a) 5 m/s b) 10 m/s c) 20 m/s d) 30 m/s e) 40 m/s 29) A jet flies at level flight. The engines produce a total of 20,000 N of forward thrust, the jets mass is 50,000 kg, and it accelerates at 0.3 m/s2. What is the magnitude of the air resistance against which the jet flies?

a) 1,000 N b) 3,000 N c) 5,000 N