PHYS 2425 Final

When a rigid body rotates about a fixed axis, all the points in the body have the same - tangential speed - angular acceleration - tangential acceleration - linear displacement - centripetal acceleration

angular acceleration

What is a vector? - a quantity having both size and direction - the rate of change of velocity - a number defined by an angle and a magnitude - the difference between initial and final displacement - none of the above

- a quantity having both size and direction

What is the vector product of A = 2.0i + 3.0j + 1.0k and B = 1.0i - 3.0j - 2.0k? - -3.0i + 5.0j - 9.0k - -5.0i + 2.0j - 6.0k - -9.0i - 3.0j - 1.0k - -4.0i + 3.0j - 1.0k - 2.0i - 9.0j - 2.0k

-3.0i + 5.0j - 9.0k

A turbine blade rotates with angular velocity w(t) = 2.00 rad/s - 2.1 rad/s^3t^2. What is the angular acceleration of the blade at t = 910s? - -38.2 rad/s^2 - -19.1 rad/s^2 - -86.0 rad/s^2 - -36.2 rad/s^2 - -172 rad/s^2

-38.2 rad/s^2

A force F = 3.00 Ni - 2.00Nj acts at a location r = 1.00mi + 2.00 mj on an object. What is the torque that this force applies about an axis through the origin perpendicular to the xy-plane? - -1.00 Nm k - 7.00 Nm k - -8.00 Nm k - 5.00 Nm k - -3.00 Nm k

-8.00 Nm k

A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s^2. Calculate the distance the block will travel if the force is applied for 10 seconds. - 75 m - 110 m - 80 m - 150 m

150 m

On its own, a certain tow-truck has a maximum acceleration of 3.0 m/s^2. What would be the maximum acceleration when this truck was towing a bus of twice its own mass? - 2.5 m/s^2 - 2.0 m/s^2 - 1.5 m/s^2 - 1.0 m/s^2

1 m/s^2

The position of an object that is oscillation on an ideal spring is given by the equation x = (12.3 cm)cos[(1.26 s^-1)t]. At time t = 0.815 s what is the magnitude of acceleration of the object? - 5.0 cm/s^2 - 10.1 cm/s^2 - 15.0 cm/s^2 - 17.0 cm/s^2 - 18.0 cm/s^2

10.1 cm/s^2

A 10,000 kg rocket blasts off from earth with a uniform upward acceleration of 2.00 m/s^2 and feels no air resistance. The upward thrust force its engines must provide during this acceleration is closest to - 20,000 N - 980,000 N - 118,000 N - 78,000 N

118,000 N

Determine the scalar product of A = 6.0i + 4.0j - 2.0k and B = 5.0i - 6.0j - 3.0k - 30i + 24j + 6k - 30i - 24j + 6k - undefined - 60 -12

12

The position of an object that is oscillation on an ideal spring is given by the equation x = (12.3 cm)cos[(1.26 s^-1)t]. At time t = 0.815 s how fact is the object moving? - 0.2777 cm/s - 10.0 cm/s - 13.3 cm/s - 15.5 cm/s - 17.0 cm/s

13.3 cm/s

A 1000 kg car is slowly picking up speed as it goes around a horizontal curve whose radius is 100 m. The coefficient of static friction between the tires and the road is 0.350. At what speed will the car begin to skid sideways? - 9.25 m/s - 23.6 m/s - 34.3 m/s - 35.0 m/s - 18.5 m/s

18.5 m/s

A ball on a massless, rigid rod oscillates as a simple pendulum with a period of 2.0 s. If the ball is replaced with another ball having twice the mass, the period will be - 6.0 s - 5.4 s - 3.0 s - 2.0 s - 1.0 s

2.0 s

If B = -2i -6j + 2k and C = -2i - 2j - 3k, which of the following numbers is closest to the magnitude of C x B? - 25 - 21 - 17 - 13 - 9

21

A child on a sled starts from rest at the top of a 15 degree slope. If the trip to the bottom takes 15.2 seconds, how long is the slope? Assume that friction forces may be neglected. - 293 m - 586 m - 1130 m - 147 m

293 m

A tire is rolling along a road, without slipping, with a velocity of v. A piece of tape is attached to the tire. When the tape is opposite the road (at the top of the tire), its velocity with respect to the road is - 2v - v - 1.5v - zero - the velocity depends on the radius of the tire

2v

A 7.0 kg object is acted on by two forces. One of the forces is 10.0 N acting toward the east. Which of the following forces is the other force if the acceleration of the object is 1.0 m/s^2 toward the east? - 6.0 N east - 3.0 N west - 12 N east - 9.0 N west - 7.0 N west

3.0 N west

Pi has the value 3.14149, express pi to four significant figures - 3.141 - 3.142 - 3.1415 - 3.1414

3.141

A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s^2. Calculate the speed of the block after the force has been applied for 10 seconds. - 5 m/s - 20 m/s - 30 m/s - 10 m/s

30 m/s

A block lies on a horizontal frictionless surface. A horizontal force of 100 N is applied to the block giving rise to an acceleration of 3.0 m/s^2. Determine the mass of the block. - 12 kg - 33 kg - 25 kg - 10 kg

33 kg

A car drives over a hilltop that has a radius of curvature of 0.120 km at the top of the hill. At what speed would the car be traveling when its tires just barely lose contact with the road when the car is at the top of the hill? - 45.5 m/s - 41.8 m/s - 34.3 m/s - 22.2 m/s - 27.6 m/s

34.3 m/s

Ball A has half the mass and eight times the kinetic energy of ball B. What is the speed ratio V(A)/V(B) - 16 - 1/4 - 2 - 4 - 1/16

4

A spring-loaded gun shoots a plastic ball with a launch speed of 2.0 m/s. If the spring is compressed twice as far, the ball's launch speed will be - 4.0 m/s - 2.0 m/s - 2.8 m/s - 3.0 m/s - 16.0 m/s

4.0 m/s

A hockey puck sliding on smooth ice at 4 m/s comes to a 1-m-high hill. What velocity would be required for the hockey puck to make it to the top of the hill? (Take g = 10 m/s^2) - 8.0 m/s - 3.0 m/s - 4.5 m/s - 10.0 m/s - 6.0 m/s

4.5 m/s

A ferris wheel has a diameter of 10 m and makes one revolution in 8.0 seconds. A person weighing 670 N is sitting on one of the benches attached at the rim of the wheel. What is the apparent weight (that is, the normal force exerted on her by the bench) of the person as she passes through the highest point of her motion? - 325 N - 250 N - 460 N - 300 N - 670 N

460 N

The ISS has a mass of 1.8 x 10^5 kg. A 70.0 kg astronaut inside the station pushes off one wall of the station as she accelerates at 1.50 m/s^2. What is the magnitude of the acceleration of the space station as the astronaut is pushing off the wall? Give your answer relative to an observer who is space walking and therefore doesn't accelerate with the station. - 5.8 x 10^-4 m/s^2 - 1.50 m/s^2 - 4.7 x 10^-4 m/s^2 - zero - 3.9 x 10^-3 m/s^2

5.8 x 10^-4 m/s^2

A 1100 kg car traveling at 27.0 m/s starts to slow down and comes to a complete stop in 578 m. What is the magnitude of the average braking force acting on the car? - 690 N - 550 N - 410 N - 340 N

690 N

A block is on a frictionless horizontal table, on earth. This block accelerates at 1.9 m/s^2 when a 90 N horizontal force is applied to it. The block and table are then set up on the moon where the acceleration due to gravity is 1.62 m/s^2. What is the weight of the block on the moon? - 77 N - 67 N - 58 N - 48 N - 39 N

77 N

A traffic light weighing 100 N is supported by two ropes at 37 degree angles. The tensions in the ropes are closest to - 50 N - 56 N - 63 N - 66 N - 83 N

83 N

A restoring force of magnitude F acts on a system with a displacement of magnitude x. In which of the following cases will the system undergo simple harmonic motion? - F is proportional to sqrt(x) - F is proportional to sin(x) - F is proportional to x^2 - F is proportional to x - F is proportional to 1/x

F is proportional to x

Two weights are connected by a massless wire and pulled upward with a constant speed of 1.50 m/s by a vertical pull P. The top weight is 25 N while the bottom weight is 100 N. The tension in the wire is T. Which one of the following relationships between T and P must be true? - T > P - T = P - P + T = 125 N - P = T + 25 N - P = T + 100 N

P = T + 25 N

A mass M is attached to an ideal massless spring. When this system is set in motion with amplitude A, it has period T. What is the period if the amplitude of the motion is increased to 2A? - 2T - T/2 - sqrt(2)T - 4T - T

T

A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15 degrees above the horizontal. IF T is the tension in this wire, then - T = ma - T > ma - T < ma

T > ma

A skier is gliding down a slope at a constant speed. What energy transformation is taking place? Assume friction force. - U to E_th - U to K - E_th to K - K to U - K to E_th

U to E_th

A skier is gliding down a slope at a constant speed. What energy transformation is taking place? Ignore friction. - U to E_th - U to K - E_th to K - K to U - K to E_th

U to K

What quantities are shown on a complete motion diagram? - the position of the object in each frame of the film, shown as a dot - the average velocity vector - the average acceleration vector - all of the above

all of the above

Which, if any, of the following statements concerning the work done by a conservative force is NOT true? - it can always be expressed as the difference between the initial and final values of a potential energy function - it is independent of the path of the body and depends only on the starting and ending points - when the starting and ending points are the same, the total work is zero - all the above statements are true - none of the above statements are true

all of the above statements are true

An object is attached to a vertical ideal massless spring and bobs up and down between the two extreme points A and B. When the kinetic energy of the object is at a minimum, the object is located - at either A or B - midway between A and B - 1/3 of the distance from A to B - 1/4 of the distance from A to B - 1/sqrt(2) times the distance from A to B

at either A or B

In a collision between two objects having unequal masses, how does magnitude of the impulse imparted to the lighter object by the heavier one compare to the magnitude of the impulse imparted on the heavier object by the lighter object? - the lighter object receives a larger impulse - both objects receive the same impulse - the heavier object receives a larger impulse - the answer depends on the ratio of the masses - the answer depends on the ratio of the speeds

both objects receive the same impulse

If we double only the mass of a vibrating ideal mass-and-spring system, the mechanical energy of the system - increases by a factor of sqrt(2) - increases by a factor of 2 - increases by a factor of 3 - increases by a factor of 4 - does not change

does not change

You swing a bat and hit a heavy box with a force of 1500 N. The force the box exerts in the bat is - exactly 1500 N only if the box does not move - exactly 1500 N whether or not the box moves - greater than 1500 N if the box moves - less than 1500 N if the box moves - greater than 1500 N if the bat bounces back

exactly 1500 N whether or not the box moves

If two vectors are perpendicular to each other, their cross product must be zero. - true - false - can't say

false

There must be equal amounts of mass on both sides of the center of mass of an object. - true - false - can't say

false

The total momentum of a system is conserved - always - if the system is isolated - if the forces are conservative - never; it's just an approximation - is unpredictable

if the system is isolated

The area under a Force versus Time is - potential energy of a particle - work done on a particle - kinetic energy on a particle - momentum of a particle - impulse force on a particle

impulse force on a particle

If we double only the spring constant of a vibrating ideal mass-and-spring system, the mechanical energy of the system - increases by a factor of sqrt(2) - increases by a factor of 2 - increases by a factor of 3 - increases by a factor of 4 - does not change

increases by a factor of 2

Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration in the x direction is correct? - both its acceleration and its velocity are positive - both its acceleration and its velocity are negative - its acceleration is positive but its velocity is negative - its acceleration is negative but its velocity is positive

its acceleration is positive but its velocity is negative

A baseball is thrown vertically upward and feels no air resistance. As it is rising - both its momentum and its mechanical energy are conserved - its momentum is not conserved, but its mechanical energy is conserved - both its momentum and its kinetic energy are conserved - its kinetic energy is conserved, but its momentum is not conserved - its gravitational potential energy is not conserved, but its momentum is conserved

its momentum is not conserved, but its mechanical energy is conserved

For general projectile motion, when the projectile is at the highest point in its trajectory - its acceleration is zero - its velocity is perpendicular to the acceleration - its velocity and acceleration are both zero - the horizontal component of its velocity is zero - the horizontal and vertical components of its velocity are zero

its velocity is perpendicular to the acceleration

Two bodies P and Q on a smooth horizontal surface are connected by a light cord, with Q to the right of P. The mass of P is greater than that of Q. A horizontal force F (of magnitude f) is applied to Q, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be - zero - less than f but not zero - equal to f - greater than f

less than f but not zero

A brick is resting on a rough incline. The friction force action on the brick, along the incline, is - zero - equal to the weight of the brick - greater than the weight of the brick - less than the weight of the brick

less than the weight of the brick

On a smooth horizontal floor, an object slides into a spring which is attached to another mass that is initially stationary. When the spring is most compressed, both objects are moving at the same speed. Ignoring friction, what is conserved during this interaction? - momentum and potential energy - momentum only - kinetic energy only - momentum and kinetic energy - momentum and mechanical energy

momentum and mechanical energy

The basic SI units are - second, meter, gram - second, meter, kilogram - second, centimeter, gram - meter, meter/second, meter/second^2 - yard, span, cubit

second, meter, kilogram

A perfectly elastic collision is a collision - between two springs - that conserves mechanical energy - that conserves kinetic energy - that conserves potential energy - that conserves thermal energy

that conserves mechanical energy

A metal bar is hanging from a hook in the ceiling when it is suddenly struck by a ball that is moving horizontally. The ball is covered with glue, so it sticks to the bar. During the collision - the angular momentum of the system (ball and bar) is conserved about the hook because only gravity is acting on the system - the angular momentum of the system (ball and bar) is not conserved about the hook because the hook exerts a force on the bar - the angular momentum of the system (ball and bar) is conserved about the hook because neither the hook or gravity exerts any torque on the system about the hook - both the angular momentum of the system (ball and bar) and its kinetic energy are conserved - both the linear momentum and the angular momentum of the system (ball and bar) are conserved

the angular momentum of the system (ball and bar) is not conserved about the hook because the hook exerts a force on the bar

The current definition of the standard second of time is based on. . . - The frequency of radiation emitted by cesium atoms - the earth's rotation - the duration of one year - the oscillation of a particular pendulum kept in France

the frequency of radiation emitted by cesium atoms

The "line of action" of a torque is - the line connecting the pivot with the point where the force acts - the axis around which the object rotates - the line that passes through the center of mass - the line along which the motion occurs - the line along with the force acts

the line along which the force acts

A horizontal disk rotates about a vertical axis through its enter. Point P is midway between the center and the rim of the disk, and point Q is on the rim. If the disk turns with constant angular velocity, which of the following statements about it are true? - P and Q have the same linear acceleration - Q is moving four times as fast as P - the linear acceleration of Q is twice as great as the linear acceleration of P - the linear acceleration of P is twice as great as the linear acceleration of Q - the angular velocity of Q is twice as great as the angular velocity of P

the linear acceleration of Q is twice as great as the linear acceleration of P

Which of the following is an accurate statement? - the magnitude of a vector can be zero even though one of its components is not zero - it is possible to add a scalar quantity to a vector - even though two vectors have unequal magnitudes, it is possible that their vector sum is zero - rotating a vector about an axis passing through the tip of the vector doesn't change the vector - the magnitude of a vector is independent of the coordinate system used

the magnitude of a vector is independent of the coordinate system used

In an INELASTIC collision between two objects - the momentum of each object is conserved - the kinetic energy of each object is conserved - the momentum of the system is conserved but the kinetic energy of the system is not conserved - both the momentum and the kinetic energy of the system are conserved - the kinetic energy of the system is conserved, but the momentum of the system is not conserved

the momentum of the system is conserved but the kinetic energy of the system is not conserved

An object is moving forward with a constant velocity. Which statement about this object MUST be true? - the net force on the object is zero - the net force on the object is in the forward direction - no forces are acting on the object - the acceleration of the object is in the forward direction

the net force on the object is zero

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be - the spring constant - the reciprocal of the spring constant - the acceleration due to gravity - the reciprocal of the acceleration of gravity - the mass of the object attached to the spring (Two answers were considered correct on this one)

the spring constant or the reciprocal of the spring constant

If the dot product of two nonzero vectors is zero, - the dot products of the vectors cannot be zero - the vectors are zero vectors - the vectors must be perpendicular to each other - the vectors are equal - the direction of one of the vectors is negative

the vectors must be perpendicular to each other

Projectiles 1 (tighter arch) and 2 (wider arch) are launched over level ground with different speeds. Both reach the same height. Which hits the ground first? Ignore air resistance. - projectile 1 hits first - projectile 2 hits first - they hit at the same time - there's not enough information to tell

they hit at the same time

For an object in uniform circular motion, its velocity and acceleration vectors are always perpendicular to each other at every point in the path - true - false

true

When an object is solely under the influence of conservative forces, the sum of its kinetic and potential energies does not change. - true - false

true

Swimmer at a water park have a choice between two frictionless water slides. Although both slides drop over the same height, h, slide 1 is straight while slide 2 is curved, dropping quickly at first and then leveling out. How does the speed v1 of a swimmer reaching the end of slide 1 compare to v2, the speed of a swimmer reaching the end of slide 2? - v1 > v2 - v1 < v2 - v1 = v2 - no simple relationship exists between v1 and v2 because we don't know the curvature of slide 2

v1 = v2

The angular momentum of a system remains constant - when the total kinetic energy is constant - when no net external force acts on the system - when the linear momentum and the energy are constant - when no torque acts on the system - all the time since it is a conserved quantity

when no torque acts on the system