Physics Exam 1 Questions with Accurate Answers Guaranteed to score an A (2025 Version).

Physics Exam 1 Questions with Accurate Answers Guaranteed to score an A (2025 Version). he mass of atoms is often given in atomic mass units (u). (1 u = 1.66*10-27 kg) The mass of a hydrogen atom is 1 u, the mass of a carbon atom is 12 u, and the mass of a oxygen atom is 16 u. Calculate the mass, in kg, of a water molecule, H2O. 2.99 X 10^-26 Can an object's velocity change direction when its acceleration is constant? yes, this is possible, and a rock thrown straight up is an example Consider motion in one dimension. (The sign of the vector quantities is their direction indicator.) An object moves in the positive x-direction with speed 1.7 m/s for 1.6 s. It stops for 2.1 s and then moves in the negative x direction with speed 3 m/s for 3.6 s. What is the total distance traveled by the object in units of meter? Enter a number with two digits behind the decimal point. 13.52 Consider motion in one dimension. (The sign of the vector quantities is their direction indicator.) An object moves in the positive x-direction with speed 8.8 m/s for 1.7 s. It stops for 3 s and then moves in the negative x direction with speed 1.8 m/s for 4.8 s. What is the average velocity of this object in units of m/s? Enter a number with two digits behind the decimal point. 0.66 A vector of magnitude 20 is added to a vector of magnitude 25. The magnitude of this sum might be 12 Consider motion in one dimension. (The sign of the vector quantities is their direction indicator.) An object moves in the positive x-direction with speed 3.5 m/s for 2.3 s. It stops for 4.8 s and then moves in the negative x direction with speed 3.1 m/s for 4.8 s. What is the displacement of this object in units of meter? Enter a number with two digits behind the decimal point. -6.83 An object is thrown straight up. At the top of its path the velocity is zero and the acceleration is equal to g pointing down. Assume you measured the position of an object in 1 second intervals at t = 1, 2, 3, and 4 seconds, and obtained x = 5.29, 11.01, 17.84, and 28.74 meters respectively. Enter these data into an Excel spreadsheet and produce a graph of position versus time, as in studio session 1. Add a trendline, and Choose "Linear" , "Display equation on chart". Format the trendline label so that it shows 3 decimal places. What is the y intercept (the best estimate of the position o the object in m at t = 0 of this trendline? Enter a number with 3 digits behind the decimal point. If the number is negative, include the sign. -3.575 A stone is thrown directly upward with an initial speed of 8.4 m/s from a height of 12.6 m. After what time interval (in s) does the stone strike the ground? Use g = 9.8 m/s2. Enter a number with 2 digits behind the decimal point. 2.675 Which of the following statements about distance and/or displacement are TRUE? (1) Distance is a vector quantity and displacement is a scalar quantity. (2) If a person walks in a straight line and never changes direction, then the distance and the magnitude of the displacement are exactly the same. (3) The diagram below depicts the path of a person walking from position A to B back to C to and then to D. The distance traveled is 90 yds. (4) For the same diagram below, the displacement of the person walking from A to B to C to D is 50 yds. Only statements 2 and 3 are true. A person walks first at a constant speed of 6 m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 4 m/s. What is her average speed over the entire trip? Hint: Assume the distance between A and B is d. How much distance does the person cover on her trip? How long does it take her to cover this distance? 4.8 m/s Another scheme to catch the roadrunner has failed and a safe falls from rest from the top of a 30.0 m high cliff toward Wile E. Coyote, who is standing at the base. Wile first notices the safe after it has fallen 15 m. How long does he have to get out of the way? 0.72 s In how many of the following situations does the car have a westward acceleration? -- The car travels westward at constant speed. -- The car travels eastward and speeds up. -- The car travels westward and slows down. -- The car travels eastward and slows down. -- The car starts from rest and moves toward the east. 1 An apple at rest weighs 1 N. Now assume the same apple is in free fall near the surface of Earth. Neglect friction. The net force on the apple while it is in free fall is 1 N An object's velocity in the positive x-direction changes from 3.6 m/s to 13.3 m/s in 2.3 s. A force of constant magnitude 20 N is acting on it. What is the object's mass in kg? Enter a number with two digits behind the decimal point. 4.74 A 1269 kg car starts from rest. A constant force of 701 N acts on it. What is the distance (in m) it travels in 2.5 s? Enter a number with two digits behind the decimal point. 1.73 In an inertial frame, an object cannot remain at rest unless which of the following holds? The net force acting on it is zero Newton's 3rd law is also called the law of action and reaction. The "reaction" force does not cancel the "action" force because they act on different bodies Your class is rather unhappy with the instructor, and they pitch in and decide to fund a sabbatical for him to go to Mars. Unbeknownst to the students the following semester, the instructor has made long distance course arrangements so the "show can go on". The instructor begins talking about mass, weight and related things. He correctly makes which following statement: his mass is still essentially unchanged but his weight is less than on earth. A car with a mass of 750 kg is moving to the right with a constant acceleration of 0.5 m/s. What is the total force (in N) on the car? Enter a integer. Round up or down correctly. 375 Is it possible to have motion in the absence of a net force? yes A 5 kg object is sliding on a surface with a coefficient of kinetic friction of 0.32. If at t = 0 it has a speed of 26 m/s, at what time (in s) will it come to rest? Let g = 9.8 m/s2. Enter a number with one digit after the decimal point. 8.3 A spring is stretched by 6.7 cm when a force of 2 N is applied. If a force of 4.3 N is applied, how many additional cm does the spring stretch? Enter a number with two digits behind the decimal point. 7.71 (A) Can two force vectors of unequal magnitude sum to zero net force? (B) Can three force vectors of equal magnitude sum to zero net force? A. no B. yes By what factor does the drag force on a car increase as its speed increases from 25 km/h to 100 km/h? 16 Refer to the diagram below. Blocks I and II, each with a mass of 1 kg, are hung from the ceiling of an elevator by ropes 1 and 2. What is the force exerted by rope 1 on block I when the elevator is travelling upward at a constant speed of 2.0 m/s? 10 N A clever physics student is able to sneak a scale on a popular ride at an amusement park. Before the ride begins to move, the scale reads 700 N for the student's weight. As the ride lifts, it initially accelerates upward at 3 m/s2. At the top, the riders are held in suspense before the gondola is allowed to free fall downward with acceleration equal to g. What should the scale read for the student's apparent weight during the lift and the fall? Lift: 910N, Fall: 0 N Two packages are dropped from an airplane. A parachute can increase the cross sectional area of each packages by a factor of 80. The parachute on package 1 fails to open, and the terminal speed of package 1 is 24.3 m/s. The parachute on package 2 opens. What is the terminal speed of package 2 in m/s? 2.7 An ideal spring with a spring constant of 4.8 N/cm and an equilibrium length of 21 cm hangs vertically from the ceiling. A 1.4 kg mass is attached to it. After all motion has damped out, what is the new length of the spring in cm? Enter a number with 1 digit behind the decimal point Let g = 9.8 m/s2.. 23.9 Two cylindrical artificial bones are made of the same material and length, one with twice the radius as the other. When the two have the same tension force applied, the larger bone stretches by what factor compared to the smaller bone .25 A driver in a car accelerating towards the right has an apparent weight with components 909 N pointing down and 599 N pointing towards the left. What is the magnitude of the acceleration of the car in m/s2? Enter a number with 1 digit after the decimal point. Let g = 9.8 m/s2. 6.5 Which of the following observations about the frictional force is incorrect? The magnitude of the force of static friction is always proportional to the normal force. You are cutting wood with a hand saw. You have to push the saw away from you as it moves away from you and pull it towards you as it moves towards you. When are you doing positive work on the saw? When pushing it away from you and when pulling it towards you. How much work (in J) must a person do to lift 2 bundles of shingles each weighing 10 pounds 14 feet onto a roof? 1 pound = 4.448 N, 1 foot = 0.305 m Enter an integer. Round up or down correctly. 380 A woman pulls a crate up a rough, inclined plane at constant speed. Which one of the following statements concerning this situation is false? The work done on the object by gravity is zero Find the magnitude of the average force (in N) needed to bring a 1672 kg car to rest from a speed of 87 km/h in a distance of 138 m. Enter an integer. Round up or down correctly. 3538 A ball is thrown straight upward. It rises in the air and then falls back to earth. Neglect friction. On the way up, kinetic energy is converted to potential energy A 2.1 kg object is brought to a stop from a speed of 1.5 m/s in 0.19 m by a spring system. What is the spring constant k of the spring? Enter an integer. Round up or down correctly. 131 Suppose you do 1000 J of work on a 4 kg object, and all the work goes into lifting it above the ground. How high above the ground will the object be when all the work has been done? 25 m In order to do a positive amount of work you must exert a force and move in the direction of the force An 4.8 kg object gains height 9.8 while being accelerated from rest to a final speed of 8.9 m/s by an external force. What was the work (in J) done on the object by this force? 651 A mass m is lowered gently onto a vertical spring of length L with spring constant k until it just touches the spring. Let y be the distance the spring is compressed and v be the velocity of the mass. The mass is released from rest. Which of the following is the equation for conservation of energy? ½mv2 + ½ky2 + mg(L - y) = mgL A boy holds a 40 N weight at arm's length for 10 s. His arm is 1.5 m above the ground. The work done by the force of the boy on the weight while he is holding it is 0 A car engine delivers 3.5 * 104 W to its wheels when moving at a constant speed of 19.1 m/s. What is the magnitude of the resistive force (in N) acting on the automobile at that speed? 1832 As a bacterium swims through water it propels itself with its flagella so as to overcome the frictional drag forces and move at, more or less, constant velocity of 100 micrometer/s for periods of time. If the frictional drag force on a bacterium is 0.1 N, how much work does the bacterium do in 1 s? 10 microJoule A block slides on a track from A to B to C to D. The section from A to B to C is frictionless, but for the section from C to D the coefficient of friction is not zero. Is the block's mechanical (ordered) energy increasing, decreasing, or constant in (a) region AB, (b) region BC, and (c) region CD? (a) constant (b) constant (c) decreasing An 4 kg object gains height 7.2 while being accelerated from rest to a final speed of 8.1 m/s by an external force. What was the net work (in J) done on the object? Let g = 9.8 m/s2. 131