Physics Exam 2

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i) Suppose a particle is moving across the monitor of your computer from left to right with the velocity vector in a horizontal direction pointing to the right. When the particle is at the center of the screen an acceleration vector is applied pointing straight down. After the acceleration vector is applied, the particle:

ii) After the acceleration vector is applied to the particle in the previous question, the particle will
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Terms in this set (31)
i) Suppose a particle is moving across the monitor of your computer from left to right with the velocity vector in a horizontal direction pointing to the right. When the particle is at the center of the screen an acceleration vector is applied pointing straight down. After the acceleration vector is applied, the particle:

ii) After the acceleration vector is applied to the particle in the previous question, the particle will
i) Will travel at constant speed

ii) Curve downward
A tennis ball following a parabolic trajectory without air resistance has two forces acting on it; gravity downward and a force keeping it moving forward
False
A grasshopper leaps into the air at a 62 degree angle above the horizontal. At its highest point, the grasshopper's velocity and acceleration are equal to zero
False
A ball is thrown upward at a 45°angle. In the absence of air resistance, the ball follows a:
Parabolic curve
A hunter points his rifle directly at a coconut that he wishes to shoot off a tree. It so happens that the coconut falls from the tree at the exact instant the hunter pulls the trigger. Consequently:
The bullet hits the coconut
A ball is thrown at an angle above the horizontal from the top of a cliff and feels no air resistance. A runner at the base of the cliff moves horizontally so that she is always under the ball. In this runner's reference frame, the path of the ball is a
Straight line
Now the cannon is pointed straight up and fired. (This procedure is not recommended!) Under the conditions already stated (drag is to be ignored) which of the following correctly describes the acceleration of the ball?
A constant downward acceleration
Bob and Biff throw identical rocks off a tall building at the same time. Bob throws his rock straight downward. Biff throws his rock downward and outward such that the angle between the initial velocity of the rock and the horizon is 30 degrees. Biff throws the rock with a speed twice that of Bob's rock. Which rock hits the ground first (assume the ground near the building is flat)?
They hit at the same time
You can launch a projectile with a fixed initial speed but at any angle above the horizontal, and it feels no air resistance. The time for it to return to the ground does not depend on the angle at which you launch it.
False
A 50 g ball rolls off a table and lands 2 m from the base of the table. A 100 g ball rolls off the same table with the same speed. It lands at a distance
2 meters from the base
For circular motion with constant speed, the acceleration:Points toward the center of the circleThe fan blades are slowing down going clockwise. What are the signs of w (omega) and a (alpha)?w is negative and a is positiveSatellites in orbit are accelerated toward the earth, so they must be getting closer and closer to our planetFalseSatellites in circular orbits around the earth are in equilibrium because they have uniform speedFalseWhat is a net force?The vector sum of all forces acting on an objectYou throw a stone vertically upward and it feels no air resistance. Once it is free of your hand but moving upward, the two forces acting on it are the downward pull of gravity and the upward force due to its motion.FalseYou've just kicked a rock, and it is now sliding across the ground about 2 meters in front of you. Which of these forces act on the ball?Gravity (acting downward), the normal force (acting upwards), friction (acting opposite the direction of motion)An object is moving with constant velocity. Which statement must be true?The net force on the object is zeroIf a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force, then its acceleration must be 3.0 m/s^2FalseA bucket is being lowered by a rope with a constant downward acceleration. The tension in the rope must be equal to the weight of the bucketFalseWhich of the following statements is true according to Newton's first law of motion?A net force is required to change an objects velocityA ball tossed straight up has v = 0 at its highest point. Is it in equilibrium?NoA box of mass m is pulled across a horizontal frictionless floor by a wire that makes an angle of 15 degrees above the horizontal. The tension in this wire isGreater than (ma)An elevator that has descended from the 50th floor is coming to a halt at the first floor. As it does, the apparent weight is"more than the true weightA block is at rest on a rough incline. The frictional force acting on the block, along the incline, is:less than the weight of the blockA 615 N student standing on a scale in an elevator notices that the scale reads 645 N. From this information, the student knows that the elevator must be moving upward.FalseA stone rolls down a sloping hillside. The normal force that the surface of the hill exerts on the stone is equal to the stone's weight.FalseA car is being towed at constant velocity on a horizontal road using a horizontal chain. The tension in the chain must be equal to the weight of the car in order to maintain constant velocity.FalseKat, Matt, and Nat are arguing about why a physics book on a table doesn't fall. According to Kat, "Gravity pulls down on it, but the table is in the way so it can't fall." "Nonsense," says Matt. "There are all kinds of forces acting on the book, but the upward forces overcome the downward forces to prevent it from falling." "But what about Newton's first law?" counters Nat. "It's not moving, so there can't be any forces acting on it." None of the statements is exactly correct. Who comes closest to the correct answer?Kat is closest to the correct statement, which should read "Gravity pulls down on it, but the table pushes it up so that the net force on the book is zero."Terminal speed isThe speed of which the drag force cancels the gravitational forceA person gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. The cart travels forward along the floor, gradually slowing as it moves. Consider the horizontal force(s) on the cart while it is moving forward and slowing. Which of the following statements is correct?Only a backward force is acting, no forward force