physics final

A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N (directed to the right). What can you say about the block's motion? A) It must be moving to the left. B) It must be moving to the right. C) It must be at rest. D) It could be moving to the left, moving to the right, or be instantaneously at rest.

D

At what angle to the ground should you kick the ball for the maximum "hang time" - that is, the maximum time in the air? A) 30∘ B) 45∘ C) 60∘ D) 90∘

D

Give a specific example of a system with the energy transformation shown. W→ΔEth A) Dropping a ball from a height. B) A block sliding on level ground, to which a cord you are holding on to is attached . C) Rolling a ball up a hill. D) Moving a block of wood across a horizontal rough surface at constant speed.

D

Suppose that a car traveling to the west (-x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration must be correct? A) Its acceleration is decreasing in magnitude as the car slows down. B) Its acceleration is zero. C) Its acceleration is negative. D) Its acceleration is positive.

D

Tennis balls experience a large drag force. A tennis ball is hit so that it goes up and then comes back straight down. The direction of the drag force is A) Always up. B) Up and then down. C) Always down. D) Down and then up

D

What is the difference between speed and velocity? A) Speed is an average quantity while velocity is not. B) Speed is measured in mph, while velocity is measured in m/s. C) The concept of speed applies only to objects that are neither speeding up nor slowing down, while velocity applies to every kind of motion. D) Velocity contains information about the direction of motion while speed does not.

D

Which of the following expressions uses the correct conversion factor to convert 35.7 km into the equivalent distance in miles? A) 35.7 km × 1 km/1.609 miles B) 35.7 km × 1 mile/1.609 miles C) 35.7 km × 1 km/1.609 km D) 35.7km × 1 mile/1.609 km

D

You throw a rock upward. The rock is moving upward, but it is slowing down. If we define the ground as the origin, the position of the rock is _____ and the velocity of the rock is _____. A) positive, negative B) negative, negative C) negative, positive D) positive, positive

D

once you have selected a coordinate system, you can express a two-dimensional vector using a pair of quantities known collectedly as ______. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

D

A baseball player is sliding into second base Identify the forces on the baseball player. A) Thrust F⃗ thrust B) Tension T⃗ C) Static friction f⃗ s D) Kinetic friction f⃗ k E) Weight w⃗ F) Normal force n⃗

D,E,F

speed differs from velocity in the same way that ______ differs from displacement. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

G

a vector has, by definition, both _____ and direction. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

H

Unlike speed, velocity is a __________ quantity. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

I

The sum of two vectors is the largest when the two vectors are _____. A) pointing in the same direction B) pointing in opposite directions C) perpendicular to each other D) positioned at a 45° angle

A

The two forces in each pair act in opposite directions. A) true B) false

A

The two forces of a 3rd law pair always act on different objects. A) true B) false

A

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 __________. A) cannot have a magnitude equal to 5N B) cannot have a magnitude equal to 10N C) cannot have the same direction as the force with magnitude 10N D) must have a magnitude greater than 10N

A

identify the following as vector quantities A) position B) displacement C) velocity D) acceleration E) distance F) average velocity G) speed

A,B,C,D,F

Which of the following is a vector quantity? A) displacement B) momentum C) force D) time E) velocity F) temperature G) acceleration H) speed

A,B,C,E,G

In uniform circular motion, which of the following quantities are constant? A) the magnitude of the net force B) instantaneous velocity C) centripetal acceleration D) speed

A,D

Velocity differs from speed in that velocity indicates a particle's __________ of motion. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

B

You drop two balls from a tower, one of mass m and the other of mass 0.5m. Just before they hit the ground, which ball, if either, has the larger kinetic energy? A) second B) first C) both balls have the same kinetic energy

B

A large crate filled with physics laboratory equipment must be moved up an incline onto a truck. The crate is at rest on the incline. What can you say about the force of friction acting on the crate? A) the frictionless force points up the incline B) the frictionless force points down the incline C) the frictionless force is zero

A

An object cannot remain at rest unless which of the following holds? A) The net force acting on it is zero. B) The net force acting on it is constant and nonzero. C) There are no forces at all acting on it. D) There is only one force acting on it.

A

Carla holds a ball 1.5 m above the ground. Daniel, leaning out of a car window, also holds a ball 1.5 m above the ground. Daniel drives past Carla at 40 mph and, just as he passes her, both release their balls at the same instant. Whose ball hits the ground first? A) The balls will hit the ground simultaneously. B) Daniel's. C) Carla's. D) The answer can't be determined from the data provided.

A

Every force has one and only one 3rd law pair force. A) true B) false

A

Consider a physical situation in which a particle moves from point A to point B. This process is described from two coordinate systems that are identical except that they have different origins. The __________ of the particle at point A differ(s) as expressed in one coordinate system compared to the other, but the __________ from A to B is/are the same as expressed in both coordinate systems. A) position B) direction C )displacement D) coordinates E) velocity F) acceleration G) distance H) magnitude I) vector J) scalar K) components

A,G

The two forces in each pair may have different physical origins (for instance, one of the forces could be due to gravity, and its pair force could be a normal contact force). A) true B) false

B

A large crate filled with physics laboratory equipment must be moved up an incline onto a truck. A physicist attempts to push the crate up the incline. The physicist senses that if he applies slightly more force the crate will move up the incline but cannot muster enough strength to get the motion started. What can you say now about the force of friction acting on the crate? A) the frictionless force points up the incline B) the frictionless force points down the incline C) the frictionless force is zero

B

A man attempts to pick up his suitcase of weight ws by pulling straight up on the handle.(Figure 1) However, he is unable to lift the suitcase from the floor. Which statement about the magnitude of the normal force n acting on the suitcase is true during the time that the man pulls upward on the suitcase? A) The magnitude of the normal force is equal to the magnitude of the weight of the suitcase. B) The magnitude of the normal force is equal to the magnitude of the weight of the suitcase minus the magnitude of the force of the pull. C) The magnitude of the normal force is equal to the sum of the magnitude of the force of the pull and the magnitude of the suitcase's weight. D) The magnitude of the normal force is greater than the magnitude of the weight of the suitcase.

B

An object moving in the +x direction experiences an acceleration of +2.0 m/s2. This means the object A) is traveling at 2.0 m/s. B) is increasing its velocity by 2.0 m/s every second. C) travels 2.0 m in every second. D) is decreasing its velocity by 2.0 m/s every second.

B

Given that two objects interact via some force, the accelerations of these two objects have the same magnitude but opposite directions. (Assume no other forces act on either object.) A) true B) false

B

If an object is speeding up, __________. A) its acceleration is positive B) its acceleration can be positive or negative depending on the direction of motion C) its acceleration is negative

B

If you kick a football, at what angle to the ground should you kick the ball for the maximum range - that is, the greatest distance down the field? A) 30∘ B) 45∘ C) 60∘ D) 90∘

B

Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct? A) The acceleration is zero. B) The acceleration is toward the east. C) The acceleration is toward the west. D) Since the car is slowing down, its acceleration must be negative.

B

The correct SI units for distance and mass are _____ and _____. A) centimeters / grams B) meters / kilograms C) feet / pounds D) meters / grams

B

The two forces in each pair can act on the same object or on different objects. A) true B) false

B

When setting up projectile motion questions, which of the following characteristics of projectile motion are important to keep in mind? A) Projectile motion is the motion of an object that moves in two dimensions under the influence of gravity and air resistance. B) Although the horizontal and vertical motions of a projectile are independent, they are connected through the time Δt that the object is in the air. C) Projectile motion is made up of two independent motions: uniform motion at constant velocity in the horizontal direction and free-fall motion in the vertical direction.

B,C

A large crate filled with physics laboratory equipment must be moved up an incline onto a truck. The first physicist gets a second physicist to help. They both push on the crate, parallel to the surface of the incline, and it moves at constant speed up the incline. How does the force exerted by the two physicists on the crate compare with the force of friction on the crate? A) the force of two physicists is less than the force of friction B) the force of two physicists equals the force of friction C) the force of two physicists is greater than the force of friction

C

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be __________. A) continuously changing direction B) moving at constant velocity C) moving with a constant nonzero acceleration D) moving with continuously increasing acceleration

C

According to Newton's 3rd law, the force on the (smaller) moon due to the (larger) earth is A) greater in magnitude than, and in the opposite direction from, the force on the earth due to the moon. B) greater in magnitude than, and in the same direction as, the force on the earth due to the moon. C) equal in magnitude to, and in the opposite direction from, the force on the earth due to the moon. D) equal in magnitude to, and in the same direction as, the force on the earth due to the moon. E) smaller in magnitude than, and in the opposite direction from, the force on the earth due to the moon. F) smaller in magnitude than, and in the same direction as, the force on the earth due to the moon.

C

Dave pushes his four-year-old son Thomas across the snow on a sled. As Dave pushes, Thomas speeds up. Which statement is true? A) The force of Thomas on Dave is larger than the force of Dave on Thomas. B) The force of Dave on Thomas is larger than the force of Thomas on Dave. C) Both forces have the same magnitude. D) It depends on how hard Dave pushes on Thomas.

C

If a block is moving to the left at a constant velocity, what can one conclude? A) There is exactly one force applied to the block. B) The net force applied to the block is directed to the left. C) The net force applied to the block is zero. D) There must be no forces at all applied to the block.

C

Now assume that the man of weight wm is tired and decides to sit on his suitcase.(Figure 2) Which statement about the magnitude of the normal force n acting on the suitcase is true during the time that the man is sitting on the suitcase? A) The magnitude of the normal force is equal to the magnitude of the suitcase's weight. B) The magnitude of the normal force is equal to the magnitude of the suitcase's weight minus the magnitude of the man's weight. C) The magnitude of the normal force is equal to the sum of the magnitude of the man's weight and the magnitude of the suitcase's weight. D) The magnitude of the normal force is less than the magnitude of the suitcase's weight.

C

For a projectile, which of the following quantities are constant during the flight: x, y, vx, vy, v, ax, ay? A) x B) y C) Vx D) Vy E) v F) Ax G) Ay

C,F,G

identify the following as scalar quantities A) position B) displacement C) velocity D) acceleration E) distance F) average velocity G) speed

E,G

which of the quantities are zero throughout the flight? A) x B) y C) Vx D) Vy E) v F) Ax G) Ay

F