MC	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Each of the following situations describes some kind of motion. Identify which of NewtonÍs three laws of motion might best explain the motion.

a. 1^st Law: Law of Inertia

b. 2^nd Law: F = ma

c. 3^rd Law: Action/Reaction

______ 1. A child riding without a safety restraint is propelled through the windshield of the car

when it is involved in an accident.

______ 2. Your friend lets you shoot his new shot gun and it makes your shoulder sore.

______ 3. A car on an icy road slides off the road while trying to negotiate a curve.

______ 4. After sitting in class for nearly an hour you are ready to announce that you are

suffering from tired bottom.

______ 5. A drag race is mostly all engine and tires.

______ 6. You have to walk to town after your car becomes stuck in the sand and you are

unable to push it out.

______ 7. A fighter plane uses a drag parachute to aid in stopping.

______ 8. In a fit of anger you swing your fist at the wall putting a hole in the wall and breaking

your hand.

Correct Answers:

1. a

2. c

3. a

4. c

5. b

6. a

7. b

8. c

MC	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Identify which of NewtonÍs laws might best explain the following situations that describe some sort of motion. Write the letter designating the law in the blank next to the description of motion. Each law may be used once, more than once, or not at all.

Laws

a. 1^st Law: Law of Inertia

b. 2^nd Law: F = ma

c. 3^rd Law: Action/Reaction

d. 4^th Law: Figs taste good

Descriptions of Motion

______ 1. A dummy riding without a seatbelt is propelled through the windshield of a

car when it crashes into a tree.

______ 2. You shoot a sawed off shot gun and it makes your shoulder sore.

______ 3. A spaceship launched into frictionless space requires no force to maintain constant velocity.

______ 4. When dropped from the same height, a 50 kg pumpkin hits the ground with a larger force than a 3 kg pumpkin.

______ 5. A Neanderthal punches a rock wall and breaks his hand.

______ 6. Galileo found that a ball rolling down one incline will pick up enough speed to roll up another.

______ 7. A skydiver uses a parachute to reach terminal velocity and prevent death.

Correct Answers:

1. a

2. c

3. a

4. b

5. c (a & b also apply)

6. a (b also applies)

7. a (c also applies)

MC	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Two balls with different masses are dropped at the same time from the roof of the school. You observe that both balls hit the ground at the same time. What can you hypothesize about the air resistance acting on each ball?

a. It is the same on both balls.

b. It is larger on the more massive ball.

c. It is larger on the less massive ball.

d. It is different, but there is no way to tell which is greater.

Correct Answer: b

MC	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Forces act on an object on a hill as shown in the diagram. What conclusion can be made about the objectÍs motion?

a. The object is motionless because the forces are balanced.

b. The object will accelerate down the hill because there is insufficient friction.

c. The object will accelerate up the hill due to the force pulling on it that direction.

d. The diagram is too inconclusive to draw any conclusions from.

Correct Answer: a

MC	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

A box is at rest on a hill. What is the correct vector diagram?

Correct Answer: c

I	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Jesse records the following data during an experiment.

Acceleration (m/s^2)	Force (N)
3	9
5	15
6	18
11	33

1. According to JesseÍs experiment, which of the following best represents the relationship between force and acceleration? (k is a constant)

a. F = k ‡ a

b. F = k ‡ a²

c. F =

d. F =

2. According to the data, what would be the correct value of k? (ignore units)

a. 6

b. 5

c. 4

d. 3

e. 2

Correct Answers:

1. a

2. d

E	Physics	Standard: 02
Objective: 02. Using NewtonÍs second law, relate the force, mass, and acceleration of an object.
ILO:

Two rides available at a local amusement park are the log flume and the train driven by a steam engine. We could compare the experience a rider might have on these two rides. Most would accept the fact that the log flume was a more exciting ride. Other rides become even more exciting than the log flume. Consider the giant roller coaster for example, or the looping roller coaster. We might ask the questions: ñWhat makes a great ride?î or ñWhy is one ride more exciting than another?î

In terms of laws of physics consider the log flume and the train. Compare (how are they alike) and contrast (how are they different) the two rides. Draw conclusions about what makes a ride exciting. Make sure you include in your explanation what the rider feels as he/she enjoys each ride. Your explanation should include consideration of forces, energy, momentum, speed, and acceleration.

Scoring Guide:

Answers will vary. Allow one point for each comparison of things alike and things different. Answers may include but are not limited to the following:

Similar: Riders ride in a car.

Start at some point and return to that same point.

Has some circular motion at some point in the ride.

For most of the ride the speed is constant for both.

For most of each ride the rider does not experience much outside force.

Different: Log flume has high acceleration from the top of the ramp.

Because of the high acceleration the rider experience forces (F = ma).

Log flume has high negative acceleration at the bottom of the ramp.

Momentum of the rider changes drastically at the bottom of the ramp.

Potential energy at the top of the ramp is converted to kinetic energy as the log falls.