Title: Summative Assessment
Course: MNPCC Physics > Section: Newton's First Law

This assessment will give you a chance to prove what you have learned during this unit.

Q: Which condition must always be met for an object to be moving at a constant speed?
- The forces on the object must be balanced. (Correct)
- The forces on the object are unbalanced in the direction of the motion. (Anytime there are unbalanced forces on an object it will accelerate.)
- The forces on the object are unbalanced in the direction opposite the motion. (Anytime there are unbalanced forces on an object it will accelerate.)
- There are no forces on the object. (While an object with no forces will not accelerate, this is not a condition that must be met, and is not a realistic condition.)
A: The forces on the object must be balanced.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which object listed below has the greatest amount of inertia?
- A 5,500 kg elephant standing in a valley. (Correct)
- A 1,700 kg rhino charging across a plain at 14 m/s. (Only mass matters.)
- A 4,000 kg truck going down the highway at 25 m/s. (Only mass matters.)
- A 1 kg rat at the top of a 8,800m mountain. (Only mass matters.)
A: A 5,500 kg elephant standing in a valley.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: A car hits an icy patch of road on a corner and continues straight into the ditch. Which statement best describes this behavior?
- Absent the friction of the road, there is insufficient force to alter the speed or direction the car is moving. (Correct)
- The ice provides a force that pushes the car to the outside of the corner, since an unbalanced force is needed to alter the path of the car from going around a corner. (The ice does not provide a force, and none is needed to go straight.)
- Some roads are banked to the outside, with the presence of the ice the car slid down the slope into the ditch. (The road may be sloped, but the lack of force is all that is needed for the car to continue in a straight line.)
A: Absent the friction of the road, there is insufficient force to alter the speed or direction the car is moving.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Why is it necessary to keep the engine of a car running to keep it moving at a constant speed down a straight flat highway?
- The engine provides a force to counter that of friction and drag. (Correct.)
- A force in the direction of motion is always needed. (Objects often move without a force in the direction that they are moving.)
- The engine counters the natural tendency for objects to come to a halt. (How very Aristotelian of you!)
A: The engine provides a force to counter that of friction and drag.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which of the following free body diagrams could not be for an object moving at a constant speed to the right?
A: (a choice with no text)
If right: Correct, this object would indeed accelerate right.
If wrong: Any time forces are balanced the object can be moving at a constant speed.
If wrong: Any time forces are balanced the object can be moving at a constant speed.
If wrong: While having no forces on an object isn’t likely, it would lead to constant speed.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which of the following is an example of a velocity?
- My car is traveling at 20 m/s due North. (Correct.)
- My car has traveled 200 mi due North. (This is a vector, but it is displacement.)
- My car is traveling 200 miles up North. (This is not a vector.)
- My car is traveling at 20 m/s on North Street. (This is not a vector quantity, I could be going any direction on North Street, least likely North.)
A: My car is traveling at 20 m/s due North.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What force were you actually measuring when pulling the shoe with the spring scale in the Mu of the Shoe Lab?
- Applied (Correct)
- Friction (Remember, the force was numerically equal to friction but only because the forces had to be balanced.)
- Gravity (Completely the wrong direction.)
- Normal (Completely the wrong direction.)
A: Applied
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: What did you find happens to the force of friction as the normal force increases in the Mu of the Shoe Lab?
- The force of friction also increases. (Correct.)
- The force of friction decreases. (Look back on your lab data.)
- The force of friction remains the same. (Look back on your lab data.)
A: The force of friction also increases.
If right: Your answer is correct.
If wrong: Your answer is incorrect.

Q: Which free body diagram best matches with the blue buggy in the Constant Velocity Graphing Lab?
A: (a choice with no text)
If right: Correct.
If wrong: The buggy has weight and a normal force!
If wrong: The buggy has an applied force and friction.
If wrong: It was moving left, but it was not accelerating.
If right: Your answer is correct.
If wrong: Your answer is incorrect.