Physics Exam 1 Basics Questions and Verified Answers Guarantee score A (LATEST VERSION).

Physics Exam 1 Basics Questions and Verified Answers Guarantee score A (LATEST VERSION). velocity whenever a net force acts on an object there is a change in the objects opposite to the direction of sliding the direction of the force of friction on a sliding crate is the newton the unit of mass is the kilogram, and unit of weight is the net force acting on it is 0 an object cannot remain at rest unless which of the following holds it could be moving to the left, right or be at rest a block of mass 2kg is acted upon two forces 3N left and 4N right, what can you say about the blocks motion moving with a constant nonzero accerleration a massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. the block must be cannot have a magnitude equal to 5N Two forces, of magnitude 4N and 10N, are applied to an object. The relative direction of the forces is unknown. The net force acting on the object __________. heavier object. Two objects of the same size, but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the the light woman A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first? 10 times as much A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is twice as much. An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be halves An object is propelled along a straight-line path in space by a force. If the mass of the object somehow becomes twice as much, its acceleration 5N An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is 10N The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is 6N A 10-N falling object encounters 4 N of air resistance. The net force on the object is 0N An apple weighs 1 N. When held at rest above your head, the net force on the apple is 1N An apple at rest weighs 1 N. The net force on the apple when it is in free fall is all of these Which has zero acceleration? An object at rest. in mechanical equilibrium. moving at constant velocity. all of these none of these is zero Whenever the net force on an object is zero, its acceleration about 1 kg. The mass of a pet turtle that weighs 10 N is has zero acceleration. An object following a straight-line path at constant speed 400 N. A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is equal to its weight. A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is 9.8 A rock is thrown vertically into the air. At the top of its path, its acceleration in meters per second per second is 5N An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, the rock has a weight of acceleration If an object of constant mass experiences a constant net force, it will have a constant force The newton is a unit of 0N A 10-N falling object encounters 10 N of air resistance. The net force on the object is no Since an object weighs less on the surface of the Moon than on Earth's surface, does it have less inertia on the Moon's surface? newtons An object's weight may properly be expressed in units of zero When a falling object has reached its terminal velocity, its acceleration is mass A kilogram is a measure of an object's magnitude and direction. A force is a vector quantity because it has both the gravitational attraction force between you and the Earth. Your weight is increases If an object's mass is decreasing while a constant force is applied to the object, the acceleration 9.8 A 1-kg mass at the Earth's surface weighs at the same time as the light block. Neglecting friction, a large block of ice and a small block of ice start sliding down an incline together. The heavier block will get to the bottom 19N; remember F=ma Calculate the horizontal force that must be applied to produce an acceleration of 1.9g for a 1.0-kg puck on a horizontal 10 times as much force. A push on a 1-kg brick accelerates it. Neglecting friction, to equally accelerate a 10-kg brick, one would have to push with 110 km/h While you're in a bus that moves at 100 km/h, you walk from the back to the front at 10 km/h. What is your speed relative to the road outside? instantaneous speed A speedometer normally measures _______. direction The difference between speed and velocity involves acceleration Galileo discovered that when air resistance can be neglected, all objects fall with the same 30 m/s A ball freely falling at 20 m/s will in the next second have a speed of _______. 1,8 m/s ; speed = distance / time Calculate your walking speed when you step 1.0 meter in 0.55 second. 60 m/s ; 30 m/s ; 180m What is the instantaneous velocity of a freely falling object 6.0s after it is released from a position of rest? What is its average velocity during this 6.0-s interval? How far will it fall during this time? 20 km/h A horse gallops a distance of 10 kilometers in a time of 30 minutes. Its average speed is zero. A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is velocity increases While an object near the Earth's surface is in free fall, its zero A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is 20 m/s. An object at rest near the surface of a distant planet starts to fall freely. If the acceleration there is twice that of the Earth, its speed one second later would be greater than the second before If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be 10 m/s. If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by about change by the same amount each second. If an object moves with constant acceleration, its velocity must 5 m/s. One half second after starting from rest, a freely falling object will have a speed of about about 180 m It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? 2 seconds. If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about velocity is zero and its acceleration is about 10 meters per second per second. When a rock thrown straight upwards gets to the exact top of its path, its 100 m/s An object falls freely from rest on a planet where the acceleration due to gravity is 20 meters per second squared. After 5 seconds, the object will have a speed of acceleration. Disregarding air resistance, objects fall with constant the same. A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about increasing. In each second of fall, the distance a freely falling object will fall is each bullet is 9.8 meters per second per second. bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, the acceleration of 9.8 meters per second per second. If you drop an object, it will accelerate downward at a rate of 9.8 meters per second per second. If you instead throw it downwards, its acceleration (in the absence of air resistance) will be 20 m/s. If a freely falling object were somehow equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s/s, then its speed reading would increase each second by 1 second. If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about 6 m/s. If a car accelerates from rest at 2 meters per second per second, its speed 3 seconds later will be about 0 An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration in meters per second per second is approximately 40 m/s At one instant a heavy object in air is moving upward at 50 meters per second. One second later its speed is approximately d= 610m ; d=1/2gt^2 Calculate the vertical distance an object dropped from rest covers in 11s of free fall. 9.8 ; d=1/2gt^2 An apple drops from a tree and hits the ground in 1.4s . Calculate how far it falls. 100 m A car accelerates at 2 meters/s/s. Assuming the car starts from rest, how far will it travel in 10 s? 64m/s ; v=gt (where g=10m/s^2) An object is dropped from rest and falls freely. After 6.4s , calculate its instantaneous speed. directed downward. A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always 22 ms ; Averagespeed=total distance covered / time interval Calculate the average speed of a cheetah that runs 110 meters in 5.0 seconds. about 180 m It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? The Sun is stationary and the Earth circles it. What did Copernicus say about the motion of the Sun? He demonstrated that light and heavy objects gain the same amount of speed when falling. What did Galileo demonstrate in his Leaning Tower of Pisa experiment? a non-zero net force Newton said that something was needed to change the motion of an object. A clear reading of his first law tells us that what is needed is _______. 10 N What is the net force when a pair of 5-N forces simultaneously act in the same direction on an object? Newton's first law Which of Newton's laws does the equilibrium rule illustrate? 200 N How much support force acts on a 200-N girl standing on a weighing scale? Zero What is the net force on a crate sliding at an unchanging speed when pushed with a steady force of 75 N? in your hand If, while riding in a smooth-riding train, you toss a coin upward, the coin will normally land It is because some force is acting upon it. A ball rolling along a floor doesn't continue rolling indefinitely. Is it because it is seeking a place of rest or because some force is acting upon it? 32 N ; 8N Consider a pair of forces, one having a magnitude of 20 N and the other a magnitude of 12 N. What maximum net force is possible for these two forces? minimum? support A force of gravity pulls downward on a book on a table. What force prevents the book from accelerating downward? 200 N If you pull horizontally on a crate with a force of 200 N, it slides across the floor in dynamic equilibrium. How much friction is acting on the crate? Galileo. The scientist to first introduce the concept of inertia was at rest. moving with constant velocity. having no acceleration. all of these An object in mechanical equilibrium is an object add up to equal your weight. Hang from a pair of gym rings and the upward support forces of the rings will always about 30 m/s. A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is exactly below the midpoint of the ceiling. A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor inertia. If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is always have forces that oppose their motion. According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains follow a straight-line path. Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to continue moving at the same velocity. If no external forces are acting on a moving object, it will 400 N A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is 10 N. The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is Earth The Greek mathematician Eratosthenes made measurements to show the size of 110 Sun diameters The distance between the Earth and the Sun is approximately a synthesis of well-tested ideas A theory in science is an agreement between trained investigators A fact in science is applying scientific discoveries Technology is a tool for _______. hypothesis In science, an educated guess is a theory. The synthesis of a large collection of information that contains well-tested and verified hypotheses about certain aspects of the world is known as a scientific wrong. A scientific hypothesis may turn out to be right or it may turn out to be wrong. If it is a valid hypothesis, there must be a test for proving it physics. Of the sciences known as physics, chemistry, and biology, the most basic is wrong A scientific hypothesis deemed valid must have a test for proving it a synthesis of a large body of well-tested knowledge. In science, a theory is may change. In science, facts coin. The easiest way for you to measure the distance between the Earth and the moon is to place in your line of sight to the moon a