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Now's the time to be TAPERED for the AP physics exams. See this post. Point is, the less we require now, the more political capital we'll gain with our students - both current students and future students.
Most students taking AP Physics are also taking other AP exams, and the teachers of those courses are putting all sorts of last minute burdens on their classes - Saturday practice exams, multiple choice practice tomes, study shaming, etc.
Think how much better our students will feel if we say "Meh, you're as ready as you're gonna be. Spend the next two weeks relaxing, doing one fundamentals quiz a day, and maybe doing a practice problem here and there with your friends." And this approach won't in any way hurt their performance on exam day.
Fundamentals Check #10:
91. An object hangs on a vertical spring. Let the position where the object hangs in equilibrium be the zero of potential energy. What is the formula for the potential energy of the spring-object-earth system? Define each variable briefly.
92. Consider a wooden block on a wooden surface. Which is larger, the coefficient of static friction between the surfaces, or the coefficient of kinetic friction?
93. An object slides up an incline which sits at an angle θ above the horizontal. What is the formula for the component of the object's weight that acts perpendicular to the incline?
94. Under what conditions does an object experience balanced forces?
95. Sophia pushes a ball to the right. After she lets go, the ball rolls right and slows down. While the ball slows down, what is the direction of the force applied by Sophia to the ball?
96. What is the weight of a 90 kg person on earth?
97. Write the kinematics equation for angular displacement under constant angular acceleration.
98. A block which weighs 100 N is attached to a string, which pulls vertically upward. The block moves upward and slows down. Is the tension in the string greater than, less than, or equal to 100 N?
99. What are the units of the coefficient of static friction?
100. Two 1 kg carts are connected by a compressed spring, and are initially at rest. The spring uncoils, causing the carts to move in opposite directions, each with 1 m/s of speed. What is the total momentum of the two-cart system after the spring uncoils?
My solutions to fundamentals check 10:
ReplyDelete91. (1/2)kx^2, where k is the spring constant and x is the distance from the place where the object hangs in equilibrium. (For a vertical spring, if you define x=0 as in this problem, you can consider all potential energy, including gravitational and spring, to be encompassed in this single formula.)
92. the coefficient of static friction.
93. mgcos(theta).
94. when it moves in a straight line at constant speed.
95. no direction; no force. (Sophia is no longer touching the ball while it slows down. In P1, all forces other than gravity require contact in order to exist.)
96. 900 N.
97. angular displacement = (w0)t + (1/2)(alpha)t^2. (Angular kinematics equations are identical in form to linear kinematics equations.)
98. less than. (Acceleration is downward, so the unbalanced force is downward, so the weight is greater than the tension.)
99. there are no units.
100. zero. (Momentums in opposite directions subtract.)