Choose the best answer to each question and write the appropriate letter in the space provided.

Transcription

1 Study Guide for Physics Mid-Term Mr. St. John Name: _ Class: Date: Choose the best answer to each question and write the appropriate letter in the space provided. 1) Which one of the following steps is NOT a part of the scientific method? A) No choices here... but there will be on the final... On certain questions, I won't give any choices... you will have to look that question up from one of your prior tests and write in the answer. On the actual midterm, I will have the same 4 choices that I gave you on the chapter test. Good luck! 2) A scientific fact is 3) The difference between a hypothesis and a theory is that a hypothesis is A) an isolated fact whereas a theory is a huge collections of facts. B) never true whereas a theory is always true. C) true whereas a theory is not true. D) never true whereas a theory is sometimes true. E) an educated guess whereas a theory has been proven true many times in many ways. 4) One difference between a hypothesis and a theory is that a hypothesis A) is not testable, whereas a theory is testable. B) is testable, whereas a theory is not testable. C) is a guess that has not been well tested, whereas a theory is a synthesis of well-tested and verified guesses. D) can be revised, whereas a theory cannot be revised. 5) Which of these is a scientific hypothesis? 6) 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 that it is A) right. B) wrong. 7) A theory is 8) As an object falls freely in a vacuum, its A) acceleration increases. B) velocity increases. C) both A and B D) none of the above 9) If you drop a feather and a coin at the same time in a tube filled with air, which will reach the bottom of the tube first? 10) One-half second after starting from rest, a freely falling object will have a speed of about 11) A ball is thrown straight up. At the top of its path its acceleration is Not Sure about the answer? Don't guess... look it up!!!!!!!!!! Page 1

2 12) Speed is 13) Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car's acceleration? 14) If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first? 15) Suppose an object is in free fall. Each second the object falls 16) When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration A) is g; no more, no less. B) varies with body orientation. C) depends on launch speed. D) depends on all the above. 17) A ball is thrown straight up. At the top of its path its instantaneous speed is 18) If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting point is about 19) Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of 20) If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by A) about 5 m/s. B) a variable amount. C) about 15 m/s. D) about 10 m/s. 21) When something falls to the ground, it accelerates. This acceleration is called the acceleration due to gravity and is symbolized by the letter g. What is the value of g on the earth's surface? 22) One possible unit of speed is 23) A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be 24) Acceleration is defined as the CHANGE in 25) 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 26) Suppose you take a trip that covers 240 km and takes 4 hours to make. Your average speed is 27) The vertical height attained by a basketball player who achieves a hang time of a full 1 second is about Prepare for the test and get an "A" Page 2

3 28) When you look at the speedometer in a moving car, you can see the car's A) instantaneous speed. B) instantaneous acceleration. C) average acceleration. D) average speed. 29) An object travels 8 meters in the first second of travel, 8 meters again during the second second of travel, and 8 meters again during the third second. Its acceleration is 30) Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's average acceleration? A) 2.5 m/s 2 B) 10 m/s 2 C) 40 m/s 2 D) 0.25 m/s 2 E) 4.0 m/s 2 31) If an object were equipped with a speedometer and allowed to fall freely on a planet where the acceleration due to gravity is 20 m/s 2, the reading on the speedometer increases each second by 32) In the absence of air resistance, objects fall at constant A) distances each successive second. B) speed. C) acceleration. D) velocity. 33) In the absence of air friction, the vertical component of a projectile's velocity doesn't change as the projectile moves. A) Sometimes true B) Always false C) Always true 34) A ball is thrown into the air at some angle. At the very top of the ball's path, its velocity is A) entirely horizontal. B) entirely vertical. C) both vertical and horizontal. 35) In the absence of air resistance, the angle at which a thrown ball will go the farthest is 36) A cannonball is launched from the ground at an angle of 30 degrees above the horizontal and a speed of 20 m/s. Ideally (no air resistance) the ball will land on the ground with a speed of 37) A projectile launched horizontally hits the ground in 0.5 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting the earth's curvature and air resistance) in 38) A ball is hurled into the air at an angle of 30 degrees above the horizontal and lands on a target that is at the same level as that where the ball started. The ball will also land on the target if it is thrown at an angle of Prepare for the test and get an "A" Page 3

4 39) An airplane flying into a head wind loses ground speed, and an airplane flying with the wind gains ground speed. If an airplane flies at right angles to the wind, then ground speed is A) unchanged. B) more. C) less. 40) Which best approximates the resultant of a pair of 10-unit vectors at right angles to each other? 41) What is the resultant of a 4-unit vector and 3-unit vector at right angles to each other? 42) If you could throw a baseball horizontally at a speed of 8 km/s and if there were no air drag and nothing to stop it, 43) At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first? A) The dropped ball B) Neither-they both hit the ground at the same time. C) The horizontally thrown ball 44) In the absence of air resistance, the angle at which a thrown ball will go the farthest is 45) A ball is thrown straight upward at 20 m/s. Ideally (no air resistance), the ball will return to the thrower's hand with a speed of 46) A cannon with a barrel velocity of 100 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, where will the cannonball be 1 second later? Choose the best answer to each question and write the appropriate leter in the space provided. 47) A 10-N force and a 30-N force act in the same direction on an object. What is the net force on the object? 48) What is the maximum resultant possible when adding a 3-N force to an 8-N force? 49) What is the minimum resultant possible when adding a 3-N force to an 8-N force? 50) How much does a 1 kg bag of nails weigh? 51) An object weighs 30 N on earth. A second object weighs 30 N on the moon. Which has the greater mass? 52) One object has twice as much mass as another object. The first object also has twice as much 53) Compared to its weight on earth, a 10-kg object on the moon will weigh Prepare for the test and get an "A" Page 4

5 54) Friction A) is the name given to the force acting between surfaces sliding past one another. B) acts in a direction that opposes the motion of an object. C) comes from microscopic bumps that act as obstructions to the object's motion. D) all of the above 55) A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that 56) The astronomer Copernicus was the first person to publicly state that the earth 57) When a woman stands with two feet on a scale, the scale reads 500 N. When she lifts one foot, the scale reads 58) The weight of a person can be represented by a vector that acts A) parallel to the ground. B) in a direction that depends on where the person is standing. C) perpendicular to the ground underneath the person. D) straight down, even if the person is standing on a hill. 59) An object following a straight-line path at constant speed A) has a net force acting on it in the direction of motion. B) has zero acceleration. C) has no forces acting on it. D) must be moving in a vacuum. 60) Which has more mass, a kilogram of feathers or a kilogram of iron? 61) Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane? 62) The mass of a dog that weighs 100 N is about 63) The law of inertia states that an object 64) After a cannon ball is fired into frictionless space, the amount of force needed to keep it going equals Choose the best answer to each question and write the appropriate letter in the space provided. 65) The acceleration produced by a net force on an object is A) directly proportional to the magnitude of the net force. B) inversely proportional to the mass of the object. C) in the same direction as the net force. D) all of the above E) none of the above Prepare for the test and get an "A" Page 5

6 66) An apple weighs 1 N. When held at rest above your head, the net force on the apple is 67) When an object reaches terminal velocity its acceleration is 68) An apple weighs 1 N. The net force on the apple when it is in free fall is 69) The terminal speed for a person parachuting (with the chute open) is about 70) A tennis ball and a solid steel ball the same size are dropped at the same time. In the absence of air resistance, which ball has the greater acceleration? 71) You pull horizontally on a 50-kg crate with a force of 500 N, and the friction force on the crate is 250 N. The acceleration of the crate is 72) A tennis ball and a solid steel ball the same size are dropped at the same time. Which ball has the greater force acting on it? 73) A girl whose weight is 200 N hangs from a bar supported by two vertical strands of rope. What is the tension in each strand? 74) Pressure is defined as 75) An object has a constant mass. A constant force on the object produces constant 76) The reason a tennis ball and a solid steel ball will accelerate at the same rate, in the absence of air resistance, is that 77) A 747 jumbo jet has a mass of kg. The thrust for each of four engines is N. What is the jet's acceleration when taking off? 78) A tow truck exerts a force of 3000 N on a car, accelerating it at 2 m/s/s. What is the mass of the car? 79) A force of 1 N accelerates a mass of 1 kg at the rate of 1 meter per second squared. The acceleration of a mass of 2 kg acted upon by a force of 2 N is 80) Which of the following would exert the most pressure on the ground? A) A woman standing on skis B) A woman standing in high heel shoes C) A woman standing in running shoes 81) A girl pulls on a 10-kg wagon with a constant force of 30 N. What is the wagon's acceleration? 82) Compared to its weight on earth, a 10-kg object on the moon will weigh A) less. B) the same amount. C) more. Prepare for the test and get an "A" Page 6

7 83) Suppose a cart is being moved by a force. If suddenly a load is dumped into the cart so that the cart's mass doubles, what happens to the cart's acceleration? 84) A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is 85) A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the frictional force between the block and the surface? 86) How does acceleration of an object change in relation to its mass? It is 87) If the force acting on a cart doubles, what happens to the cart's acceleration? 88) When the angle of an incline with a block resting on it increases, the normal support force A) increases. B) stays the same. C) decreases. 89) A person is attracted towards the center of the earth by a 500-N gravitational force. The force with which the earth is attracted toward the person is A) 500 N. B) very very large. C) very very small. 90) A player hits a ball with a bat. The action force is the impact of the bat against the ball. What is the reaction to this force? 91) Bronco the skydiver falls toward the earth. The attraction of the earth on Bronco pulls him down. The reaction to this force is 92) A Mack truck and a Volkswagen traveling at the same speed have a head-on collision. The vehicle to undergo the greater change in velocity will be the A) Volkswagen. B) Mack truck. C) Both the same 93) The earth pulls on the moon, and similarly the moon pulls on the earth. This is evidence that the 94) Whenever an object exerts a force on another object, the second object exerts a force of the same magnitude, but in the opposite direction to that of the first object. A) Always false B) Always true C) Sometimes true 95) A high school student hits a nail with a hammer. During the collision, there is a force 96) According to Newton's third law, if you push gently on something, it will push 97) Forces always occur A) as single quantities. B) in pairs. C) in triplets. D) by themselves. Prepare for the test and get an "A" Page 7

8 98) An archer shoots an arrow. Consider the action force to be the bow string against the arrow. The reaction to this force is the 99) An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is 100) An unfortunate bug splatters against the windshield of a moving car. Compared to the deceleration of the car, the deceleration of the bug is A) smaller. B) the same. C) larger. 101) A force is exerted on the tires of a car to accelerate the car along the road. The force is exerted by the A) air. B) tires. C) road. D) engine. 102) A karate chop delivers a blow of 3000 N to a board that breaks. The force that acts on the hand during this feat 103) Two objects, A and B, have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, but A has a higher 104) A 1-N apple falls to the ground. The apple hits the ground with an impact force of about 105) Suppose an astronaut in outer space wishes to play a solitary "throw, bounce, and catch" game by tossing a ball against a very massive and perfectly elastic concrete wall. If the ball is as massive as the astronaut, then 106) The force that accelerates a rocket into outer space is exerted on the rocket by the 107) Momentum of a system is conserved only when 108) A cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the 109) The force of an apple hitting the ground depends upon 110) In order to increase the final momentum of a golf ball, we could A) follow through when hitting the ball. B) increase the force acting on it. C) swing as hard as possible. D) increase the time of contact with the ball. E) all of the above Prepare for the test and get an "A" Page 8

9 111) A small economy car (low mass) and a limousine (high mass) are pushed from rest across a parking lot, equal distances with equal forces. The car that receives the greater impulse is the 112) A cannon fires a cannonball. The speed of the cannonball will be the same as the speed of the recoiling cannon A) because velocity is conserved. B) because both velocity and momentum are conserved. C) if the mass of the cannonball equals the mass of the cannon. D) because momentum is conserved. 113) In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because 114) If the momentum of an object changes and its mass remains constant, A) its velocity is changing. B) there is a force acting on it. C) it is accelerating (or decelerating). D) all of the above 115) If all people, animals, trains and trucks all over the world began to walk or run towards the east, then 116) Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil velocity will be A) the same as before. B) zero. C) small but noticeable. 117) When you jump off a step, you usually bend your knees as you reach the ground. By doing this, the time of the impact is about 10 times more what it would be in a stifflegged landing and the average force on your body is reduced by A) more than 10 times. B) less than 10 times. C) about 10 times. 118) A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has 119) The momentum of an object is defined as the object's 120) Suppose a girl is standing on a pond where there is no friction between her feet and the ice. In order to get off the ice, she can A) get on her hands and knees and crawl off the ice. B) walk very slowly on tiptoe. C) throw something in the direction opposite to that in which she wants to go. D) bend over touching the ice in front of her, then bring her feet to her hands. 121) Superman is at rest in space when he throws an asteroid that has more mass than he does. Which moves faster, Superman or the asteroid? Prepare for the test and get an "A" Page 9

10 122) A Ping-Pong ball launcher is fired. Compared to the force on the ball, the force on the launcher is A) smaller. B) the same. C) larger. 123) A 2-kg ball is thrown at 3 m/s. What is the ball's momentum? 124) A ball is moving at 4 m/s and has a momentum of 48 kg m/s. What is the ball's mass? 125) The momentum change of an object is equal to the 126) Two gliders having the same mass and speeds move toward each other on an air track and stick together. After the collision the velocity of the gliders is A) twice the original velocity. B) zero. C) one half the original velocity. D) the same as the original velocity. 127) The reason padded dashboards are used in cars is that they A) decrease the momentum of a collision. B) increase the time of impact in a collision. C) increase the force of impact in a collision. D) look nice and feel good. E) decrease the impulse in a collision. 128) While rollerblading, Granny collides with her tiny grandson Ambrose who is at rest. Ignoring any friction effects, Ambrose's speed after the collision will be greatest when A) Granny catches him and they both move together. B) he and Granny make a bouncing collision, each going separate ways. 129) A Ping-Pong ball launcher is fired. Compared to the impulse on the ball, the impulse on the launcher is A) smaller. B) the same. C) larger. 130) A 4-kg ball has a momentum of 12 kg m/s. What is the ball's speed? 131) Suppose a cannon is made of a strong but very light material. Suppose also that the cannonball is more massive than the cannon itself. For such a system A) recoil problems would be lessened. B) conservation of energy would not hold. C) the target would be a safer place than where the operator is located. D) conservation of momentum would not hold. E) the force on the cannonball would be greater than the force on the cannon. Finally!!!!!! You're ready for my final!!!!!!!