physics 1 final

The displacement x of an objects moving along the x axis is shown below as a function of time t the acceleration of this object must be ... (its a p vs t graph linear / )

0

The cart of mass 10 kg shown above moves without frictional loss on a level table. A 10 N force pulls on the cart horizontally to the right. At the same time, a 30 N force at an angle of 60 degrees above the horizontal pulls on the cart to the left. What is the magnitude of the horizontal acceleration of the cart.

0.5 m/s^2

Three objects can only move along a straight level path. The graphs below show the positions d of each of the objects plotted as a function of time t. The sum of the forces on the object is zero in which of the cases. (1 is a linear line 2 is a straight horizontal line and 3 is a curving up line)

1 and 2

Two blocks of masses 1.0 kg and 2.0 kg respectively are pushed by a constant applied force f ACROSS A HORIZONTAL FRICTIONLESS TAQBLKE WITH CONSTANT ACCELERATION SUCH THAT THE BLOCKS REMAIN IN CONTACT WITH EACH OTHER ASH SHOWN ABOVE. The 1.0 KG BLOCK PUSHES THE 2.0 KG block with a force of 2.0 N the acceleration of the blocks is

1 m/s^2

The system shown above is released from rest. IF friction is negligible, the acceleration of the 5.0 kg sliding on the table shown above is nearly

3.3 m/s^2

A box is given a sudden push up a ramp. Friction between the box and the ramp is not negligible. Which of the following diagrams best represents the directions of the actual forces acting on the box as it moves upward after the push.

A (box on ramp with friction to left fn perpendicular to box and gravity straight down.)

Three identical blocks X Y and Z hang from identical strings, as shown in the figure. Which of the followings FBD could represent the forces exerted on block Y.

B (Ftension up Ftension down/Fg down)

At t=0 a moving cart on a horizontal track is at position 0.5m using a motion detector, students generate a graph of the carts velocty as a function of time as shown above. At time t=1.0s the carts position is most nearly

D 2m

A student stands at one end of a raft floating in a pool with equally spaced marks along the bottom, as shown above. The student and the raft have the same mass. The student walks to the opposite end of the raft. Which of the following best shows the final locations of the raft and student relative to the marks at the bottom of the pool? assume there is no drag force between the raft

D raft all the way to the left

The graphs above show the magnitude F of a force exerted on an object as a function of the object's positions x for two trials in an experiment. W1 and W2 are the work done on the objects by force q and force 2. How do w1 and w2 compare and why.

W1 < w2 because there average value of force 1 is smaller than the average value of force 2

Which of the following is true at time t=20 seconds

cart y is being car x

Box A a mass m sits on the floor of an elevator, with box b of mass 2m on top of it as shown in the figure above. The elevator is moving upward and slowing down. FA is the magnitude of the force exerted on box a by box b, FB is the magnitude of the force exerted on box B by box A and fg is the magnitude of the gravitational force exerted on box B. Which of the following ranks the forces in order of increasing magnitude

(Fb=Fa)<Fg

What is the displacement traveled according to the graph below

-3m

A 50.0 N box is a rest on a horizontal surface. The coefficient of a static friction between the box and the surface is 0.50 and the coefficient of friction is 0.30. A horizontal 20.0 N force is then exerted on the box. The magnitude of the acceleration of the box is most nearly.

0 m/s^2

Three forces act on an object. If the object is in translational equilibrium which of the follow must be true. 1. the vector sum of the three forces must equal zero 2. the magnitudes of the three forces must be equal 3. all three forces must be parallel

1 only

To analyze the characteristic and performance of the brakes on a 1500 kg car, researchers collected the data shown in the table above. It shows the car's speed when the brakes are first applied and the corresponding braking distance required to stop the car. The magnitude of the average braking force on the car is most nearly. (speed 10 20 30 braking distance 6.1 23.9 53.5)

12000 N

The figure shown above shows the forces exerted on a block that is sliding on a horizontal surface: the gravitation force of 40 N the 40 N normal force exerted by the surface and a frictional force exerted to the left the coefficient of friction between the block and the surface is 0.2 the acceleration of the block is most nearly.

2.0 ,m/s^2 to the left

In a lab weighing 80 N is attached to a spring scale and both are pulled to the right on a horizontal surface, as shown above. Friction between the block and the surface is negligible. What is the acceleration of the block when the scale reads 32 N

4 m/s

A car travels 30 miles at an average speed of 60 mph then 30 miles at an average of 30 mph the average speed over the 60 mph is

40

a block on a horizontal surface of negligible friction is placed in contact with an ideal spring, as shown above. The block is moved to the left so that the spring is compressed a distance x from equilibrium and then released from rest. The block has kinetic energy K when it separates from the spring. When the spring is compressed a distance 2x and the block is released from rest the kinetic energy of the block when it separates from the spring is

4k

A ball is dropped from rest and falls to the floor. The initial gravitational potential energy of the ball earth floor system is 10J./ The ball then bounces back up to a height where the gravitational potential energy is 7 J. What was the mechanical energy of the ball earth floor system the instant the ball left the floor.

7 J

A rocket is consciously firing its engines as it accelerates away from Earth. For the first kilometer of its ascent the mass of fuel ejected is small compared to the mass of the rocket. For this distance which of the following indicates the changes, in the kinetic energy of the rocket the gravitational potential energy of the earth rocket system, and the mechanical energy of the earth rocket system?

A (all increasing)

The free fall trajectory of an object thrown horizontally from the top of a building is shown as the dashed line in the figure. Which sets of arrows best correspond to the directions of the velocity and of the acceleration for the object at the point labeled b on the trajectory?

A (velocity \ (down to right) acceleraetion straight down arrow)

The inclined plane in the figure above has two sections of equal length and different roughness. The dashed line shows where section 1 ends and section 2 begins. A block of mass M is placed at different locations on the incline. The coefficients of kinetic and static friction between the block and each section are shown in the table below. If the block is sliding up section 2 what is the magnitude of the force of friction that is exerted on the block by the incline

A 2uk Mg Cos theta

An object undergoes an acceleration as it travels along a straight horizontal section of a track. Which of the following graphs could represent the motion of the object? select two answers

A and D (speed vs time graph speed starts high, position vs time squared graph position starts high

The Atwood's machine shown consists of two blocks of mass m1 and m2 that are connected by a light string that passes over a pulley of negligible friction and negligible mass. the block of mass m1 is a distance h1 above the ground and the block of mass m2 is a distance h2 above the ground m2 is larger than m1 the two-block system is released from rest. which of the following claims correctly describes the outcome after the blocks are released from rest but before the block of m2 reaches the ground 2 answers

A and D for the system consisting of the two blocks the change in the kinetic energy of the system is equal to the work done by gravity on the system. For the system consisting of the two blocks, the pully and earth the change in the total mechanical energy of the system is zero.

The velocity of a projectile at launch has a horizontal component v0 and a vertical component v0. Air resistance is negligible. When the projectile is at the highest point of its trajectory, which of the following shows the vertical and horizontal components of its velocity and the vertical component of its acceleration.

A vertical velocity 0 horizontal velocity vh vertical acceleration 0

A kitten sits in a lightweight basket near the edge of a table./ a person accidently knocks the basket off the table. AS the kitten and basket fall the kitten rolls turns kicks and catches the basket in its claws. The basket lands on the floor with the kitten safely inside. If air resistance is negligible, what is the acceleration of the kitten basket system while the kitten and basket are in midair.

B ( the acceleration is directed downward with magnitude equal to g because the system is a projectile)

An object of mass m is initially at rest and free to move without friction in any direction in the xy-plane. A constant net force of magnitude F directed in the +x direction acts on the object for 1s immediately thereafter a constant net force of the same magnitude f directed in the +y direction acts on the object for 1s. After this no forces act on the object. Which of the following graphs represents the kinetic energy k of the object as a function of time,.

B (1s curves up stops 2s curves up again 3sstraight)

Two students want to determine the speed at which a ball is released when thrown vertically upward into the air. One student throws the ball into the air while the other students measure the total time the ball is in the air. The students use a meterstick to measure the release height of the ball which of the following equations should the students use to determine the speed at which the ball is released

B (use y = yo + vyot+ 1.2 at^2)

The figure above shows the net force exerted on an object as a function of the position of the object. The object starts from rest position x=0 and acquires a speed of 3,0 m/s after traveling a distance of 0.09m what is the mass of the object.

B 0.030 kg

An object with mass m is suspended at rest from a spring with a spring constant of 200 N/m. The length of the spring is 5.0 cm longer than its unstretched length L (5 cm) What is the total energy stored in the spring at the new stretched length?

B 1.0 J

A 2.0kg disk can move on a straight-level track with negligible friction. With the disk initially at rest a horizontal force is applied to the disk. The force is measured as a function of the disks displacement and the data are shown in the graph. When the disks displacement is 2.0 m/s the speed of the disk is most nearly.

B 4.0 m/s

A 6kg sled starts from rest at the top of a hill and slides down the hill as shown above. As the sled passes through a part that is 30m vertically below its starting point, it has a speed of 20 m/s. How much mechanical energy was dissipated by frictional forces during the interval shown,

B 600J

A vertical spring has unstretched length Lo as shown in figure 1. A block is attached to the top of the spring and slowly lowered until it is at rest and the spring has length leq as shown in figure 2. The block is then pushed down until the spring is compressed to length lcomp as shown in figure 3 and then released after release at what height will the kinetic energy of the block be maximum.

B Leq

A student performs an experiment in which the horizontal position of a toy car is recorded on ticker tape from a device that places dots on the tape in equal time intervals. The series of dots in the figure represents the motion of an object moving from the negative direction to the position direction along the horizontal direction; The time interval between each recorded dot is 1 sec. Which of the following experiments could the student have consumed cited to create the data shown on the ticker tape?

B a toy car that initally increases its speed travels at a constant speed then decreases its speed.

A force F0 is applied continuously to a box initially at rest on a horizontal surface. The box slides with negligible friction for equal distances d1 and d2 as shown. How does the kinetic energy gained by the block over distance interval d2 change k2 compared to the kinetic gained over d1 and changek1 and why?

B k2 = k1 because the applied force does the same work on the block over intervals d1 and d2

A block of mass m slides with speed v along a frictionless horizontal surface toward an unstretched spring attached to a wall as shown above. The block compresses the spring a maximum distance changeX. Which of the following values of block mass and initial speed would result in the same maximum compression distance changeX for spring.

Block mass 2m intial speed v/4

A projectile launched from a cliff at time t=0 follows the path indicated by the dashed line in the above figure. the axes indicate the positive horizontal and vertical direction. which of the following graphs could represent the projectiles motion.

C ( negative linear graph starting at intial velocity)

A block is pulled along a surface of negligible friction by a spring scale that exerts a force f ON THE BLOCK. The mass of the block is 4kg and the spring scale reads 10N. Which of the following free body diagrams can be used to show the magnitude and direction of all the forces exerted on the block as it is pulled along the surface.

C (fn and fg are balanced fspring is smaller than fn and fg)

A block slides down an inclined plane whose roughness varies. ONly during time interval 1 does the block slide with negligible friction. The coefficient of kinetic friction during time interval 3 is twice the coefficient of kinetic friction during time interval 2. THe graph shows the velocity of the block as a function of time. The table lists the mechanical energy dissipated due to friction over the different time intervals. Which of the following claims is true.

C (w3 > w2 > w4)

A diver initially moving horizontally with speed v dives off the edge of a vertical cliff and lands in the water a distance d from the base of the cliff. How far from the base of the cliff would the diver have landed if the diver initially had been moving horizontally with speed 2v.

C 2d

Three stones of different masses (1m 2m 3m) are thrown vertically upward with different velocities (1v 2v and 3v) the diagram indicates the mass and velocity of each stone. Rank from high to low the maximum height of each stone assume air resistance is negligible.

C 3 2 1

The graph shows the acceleration as a function of time for an object that is at rest at time t=0 sec the distance travelled by the object between 0 and 2 s is most nearly

C 3m

A whiffle ball is tossed straight up reaches a highest point and falls back down. Air resistance is not negligible. Which of the following statements are true? 1. The balls speed is zero at the highest point 2. The balls acceleration is zero at the highest point 3. the ball takes a longer time to travel up to highest point than to fall back down.

C I and II

The pendulum shown in the figure above reaches a max height h above the equilibrium position as it oscillates. Assuming friction and air resistance are negligible which of the following is true about the total energy of the earth-pendulum system as the pendulum oscillates?

C it is constant throughout the pendulum's motion

A cart is constrained to move along a straight line. A varying net force along the direction of motion is exerted on the cart. The cart's velocity v as a function of time t is shown in the graph above. The 5 labeled points divided the graph into four sections during some part of the motion the work done on the cart is negative what feature of motion indicates this.

C speed is decreasing

A rockl of mass m is thrown horizontally off a building from a heigh h as shown above. the speed of the rock as it leaves the throwers hand at the edge of the building is v0. how much time does it take the rock to travel from the edge of the building to the ground?

C sqrtr 2h/g

A projectile is fired with inital velocity vo at an angle T0 with horizontal and follows the trajectory shown above. Which of the following pairs of graphs best represents the vertical components of the velocity and acceleration v and a respectively of the projectile as function of time t.

D ( one graph -9.81 straight line and other stars from velocity then goes down)

A block of mass m is released from rest and slides down an incline as shown in the figure. The length L of the incline is 0.8m and the angle of the incline theta is 37 degrees. A graph of speed v as a function of the time t of the block as it descends the incline is shown how could a student use the graph and the information provided to determine whether the block earth system is an open system or a closed system?

D (determine final kinetic energy as described above and compare it with the initial gravitation potential energy of the block earth system as described above)

A 10 kg block is attached to a light cord that is wrapped around the pulley of an electric motor as shown above. At what rate is the motor doing work when it is pulling the block upward with an instantaneous speed of 3 m.s and an upward acceleration of 2 m/s^2

D 360W

The diagram below shows 3 cannons firing shells with different masses at different masses at different angles of elevation. The horizontal component of the shells velocity is the same in all four cases. In which case will the shell have the greatest range if air resistance is neglected.

D Both cannons B and C have the greatest range.

The force diagram shows a box accelerating to the right on a horizontal surface of non-negligible friction. The tension is exerted at an angle of 30 degrees above the horizontal. If u is the coefficient of kinetic friction between the box and the surface which of the following is a correct mathematical equation derived by applying newtons second law to the box?

D Tcostheta umg Tsingtheta/m

A student drops a rock from the top of a cliff such that the rock falls downward toward earths surface in the absence of air resistance. the downward direction is considered to be the positive direction. the graph shows the rock's velocity as a function of time.; which of the following statements is correct?

D at 4 seconds the object travels 80m and its acceleration is 10 m/s/s

A large beach ball is dropped from the ceiling of a school gymnasium to the floor about 10 meters below. Which of the following graphs would best represent its velocity as a function of time? (do not neglect air resistance)

D graph like sqrt of x

Balls 1 and 2 are reach thrown horizontally from the same height above level ground, but ball 2 has aa greater initial velocity after leaving the throwers hand.. If air resistance is negligible how do the accelerations of the balls and the times it takes them to hit the ground compare?

E The acceleration and the time to hit ground aare both equal

Two blocks of masses m and M are suspended as shown above by strings of negligible mass. If a person holding the upper string lowers the blocks so that they have a constant downward acceleration a, the tension in the string at point P is

M(g-a)

A crate is on a horizontal frictionless surface. A force of magnitude F is exerted on the crate at an angle theta to the horizontal in the figure above. Causing the crate to slide to the eight. The surface exerts a normal force of magnitude FN on the crate, As the crate slides a distance d it gains an amount of energy. While F is kept constant the angle theta is now doubled but is still less than 90 degrees. Assume the crate remains in contact with the surface. How does the new normal force exerted on the crate compared to FN,

The new normal force is less than FN

A block of mass m is released from rest a point 1 as shown in the figure. The block slides without frictional forces along the circular arc but encounters frictional forces as soon as it reaches the horizontal portion of the trach at point 2. The block travels a distance D along the horizontal track before coming to rest a point 3. Consider the block earth system. In terms of the mechanical energy of the system which of the following claims is correct and why?

The system is open because there is a net force exerted on the block.

A person holds a book at rest a few feet above a table. The person then lowers the book at a slow constant speed and places it on the table. Which of the following accurately describes the change in the total mechanical energy of the earth book system.

The total mechanical energy decreases because the person does negative work on the book by exerting a force on the book in the opposite direction to its displacement.

Would you need to linearize this graph (it like sqrt x)

Yes

An engineer measures the velocity v of a remote controlled cart on a straight track at regular time intervals. The data are shown in the graph above. During which of the follow time intervals did the cart return to its position at time t=0.

c (7s < t < 10 s)

An object is released from rest on a planet that has no atmosphere. the object falls freely for 3.0 meters in the first seconds what is the magnitude of the acceleration due to gravity on the planet.

c 6.0 m/s^2

The inclined plane in the figure above has two sections of equal length and different roughness. The dashed line shows where section 1 ends and section 2 begins. A block of mass M is placed at different locations on the incline. The coefficients of kinetic and static friction between the block and each section are shown in the table below. If the block is at rest on section 1 of the incline what is the magnitude of the force of static friction exerted on the block by the incline

mg sin theta

a motion sensor is used to create the graph of a student's horizontal velocity as a function of time as the students moves toward and away from the sensor as shown above. The postive direction is defined as the direction away from the sensor. Which of the following describes the student final position x in relation to the starting position xo and the student average horizontal acceleration ax between 0.0 and 3.,0 s

position xf is farther away from the sensor than xo and ax is negative

A person is running on a track which of the following forces propels the runner forward

the force of friction exerted by the ground on the person.

An object is moving to the right with speed vi when a force of magnitude f is exerted on it which of the following situation is the object direction of motion changing and the kinetic energy decreasing at instant shown.

vi is going right and F is like \