Unit 3 Test Flashcards by dhruv patel

(a) 0.06m
(b) 0.2 m
(c) 0.5 m
(d) 0.8 m

(b) 0.2m

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Which of the following graphs of potential energy U as a function of position x has a point of stable equilibrium at x_0.

(a)
(b)
(c)
(d)

(d) the U shape under x axis

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(a) 1/2 Mgd
(b) Mgd
(c) 2Mgd
(d) 4Mgd

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(a) kx^3
(b) 1/2 kx^2
(c) 1/2 kx^3
(d) 1/3 kx^2
(e) 1/3 kx^3

(e) 1/3 kx^3

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(a) -18a + 4
(b) -18a - 4
(c) 18a - 4
(d) 3a^3 - 2a^2
(e) -3a^3 +2a^2

(a) -18a + 4

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(a) 1/2 k (D)^2
(b) e^kD
(c) -ke^kD
(d) 1/k (e^kD - 1)

(d) 1/k (e^kD - 1)

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(a) 1/2 kD^2
(b) 3/7 kD^7/3
(c) 1/2 kD^8/3
(d) 4/3 kD^1/3

(b) 3/7 kD^7/3

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(a) 0 m/s
(b) 2.24 m/s
(c) 2.74 m/s
(d) 5 m/s
(e) 7.5 m/s

(b) 2.24 m/s

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(a) x = 4m
(b) x = 10m
(c) x = 5 m and x = 15m
(d) Between x = 18 m and x = 20m
(e) At no point on the graph does the object come to rest

(e) At no point on the graph does the object come to rest

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(a) U_sys increases only
(b) U_sys decreases only
(c) U_sys decreases and then increases
(d) U_sys does not change

(a) U_sys increases only

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(a) 4.0 J
(b) 8.0 J
(c) 12 J
(d) 16 J

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(a) 12a
(b) 2a^3 - a^2
(c) 14a^3 - 3a^2
(d) 42a^3 - 6a^2

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(a) 2 m/s
(b) sqrt(5) m/s
(c) 2sqrt(3) m/s
(d) 5 m/s

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(a) F_s = 9x^2 - 8x + 2
(b) F_s = -9x^2 + 8x - 2
(c) F_s = 3/4 x^4 - 4/3 x^3 + x^2
(d) F_s = -3/4 x^4 + 4/3 x^3 - x^2

(b) F_s = -9x^2 + 8x - 2

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(a) U = 3k (1/x^4 - 1/x^4)
(b) U = 1/2k (1/x^4 - 1/x^4)
(c) U = 2k (1/x^4 - 1/x^4)
(d) U = k (1/x^4 - 1/x^4)
(e) U = 1/4k (1/x^4 - 1/x^4)

(b) U = 1/2k (1/x^4 - 1/x^4)

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(a) 0.026 J
(b) 1.6 J
(c) 3.2 J
(d) 125 J
(e) 26000 J

(a) 0.026 J

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(A) It oscillates with maximum position x2 and minimum position x0
(B) It moves to the right of x3 and does not return.
(C) It moves to the left of x0 and does not return.
(D) It comes to rest at either x0 or x2
(E) It cannot reach either x0 or x2.

(E) It cannot reach either x0 or x2.

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(a) 1 * 10^-6 N
(b) 5 * 10^-5 N
(c) 2 * 10^-3 N
(d) 5 * 10^-2 N
(e) 1 * 10^-1 N

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An object is initially at rest at the origin of the x-axis. A single conservative force is exerted on the object. The force F_x as a function of position x is shown in the graph provided. Which of the following sets of graphs best show the potential energy of the system and the kinetic energy of the object as the object moves away from the origin?
(a) straight line up straight line up
(b) straight line up straight line down
(c) curved up curved up
(d) curved up curved down
(e) curved up straight line up

(d) curved up and curved down

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(a) 1/2 v
(b) 1/4 v
(c) 1/ sqrt(2)
(d) sqrt(2) v
(e) 2v

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(a) F only
(b) F and D only
(c) F, H, and t
(d) H, t, and D
(e) F, D, and H

(e) F, D, and H

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(a) x = 0 only
(b) x = a/k only
(c) x = 2a / k only
(d) x = 0 and a/k
(e) x = 0 and 2a/k

(b) x = a/k only

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(a) Zero
(b) msqrt(gh)
(c) msqrt(2gh)
(d) msqrt(4gh)
(e) msqrt(8gh)

(e) msqrt(8gh)

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(a) x_MAX = 2.0m and v_MAX = 1.4 m/s
(b) v_MAX = 1.4 m/s and v_MAX = 0.20m/s
(c) x_MAX = 0.20 m and v_MAX = 1.4 m/s
(d) x_MAX = 0.40m and v_MAX = 1.4 m/s
(e) x_MAX = 0.04 m and v_MAX = 2.0 m/s

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(a) 2/7 R (b) 2/5 R (c) 5/7 R (d) 7/5 R

(b) 2/5 R

(A) The object will move toward Planet A and the gravitational potential energy of the system will decrease. (B) The object will move toward Planet A and the gravitational potential energy of the system will increase. (C) The object will move toward Planet B and the gravitational potential energy of the system will decrease. (D) The object will move toward Planet B and the gravitational potential energy of the system will increase.

(A) The object will move toward Planet A and the gravitational potential energy of the system will decrease.

(A) U_g decreases because the gravitational force of each asteroid does negative work on the spacecraft. (B) U_g decreases because the gravitational force of each asteroid does positive work on the spacecraft. (C) U_g increases because the gravitational force of each asteroid does positive work on the spacecraft. (D) U_g increases because the gravitational force of each asteroid does negative work on the spacecraft.

(B) U_g decreases because the gravitational force of each asteroid does positive work on the spacecraft.

An object is pushed into nonideal spring, compressing the spring. The magnitude of force F the spring exerts on the object as a function of compression x is shown in the graph. Which of the following graphs best shows the potential energy of the object-spring system as a function of x? (a) straight line up (b) straight line down (c) curved line up (d) curved line down

(a) The system has zero potential energy (b) Particle A has 2.0 J of kinetic energy (c) The system has 2.0 J of total mechanical energy (d) Particle A is always at x = 0.40m (e) Particle A oscillates between x = 0.20m and 0.65 m

(e) Particle A oscillates between x = 0.20m and 0.65 m

The x-component of the force on particle A when it is at x = 0.15m is most nearly (a) - 20N (b) -2.0 N (c) -1.0 N (d) 2.0 N (e) 20 N

(e) 20 N

(a) 20 N (b) 10 N (c) 4.0 N (d) 1.0 N (e) 0.25 N

(d) 1.0 N

(a) Mg/a (b) Mgv/2A (c) Mv^2 / 2A (d) Mv^2 / A^2 (e) Mv^2 / 2A^2

(d) Mv^2 / A^2

(a) B/4D^2 + Mv^2 = B/r^2_MIN + M(v/2)^2 (b) B/4D^2 + 1/2Mv^2 = B/r^2_MIN + M(v/2)^2 (c) B/4D^2 + 1/2Mv^2 = B/r^2_MIN + 1/2M(v/2)^2 (d) B/4D^2 + 1/2Mv^2 = B/r^2_MIN (e) B/4D^2 + Mv^2 = B/r^2_MIN

(b) B/4D^2 + 1/2Mv^2 = B/r^2_MIN + M(v/2)^2

(a) 1 = 2 = 3 (b) 1 > 2 > 3 (c) 1 > 3 > 2 (d) 2 > 1 > 3 (e) 3 > 1 > 2

(e) 3 > 1 > 2

(a) d2 < d1, because block 2 reaches its maximum speed later than block 1 (b) d2 < d1, because block 2 has a lower maximum speed later than block 1 (c) d2 = d1, because blocks have the same mass (d) d2 = d1, because the blocks start at the same height (e) d2 > d1, because the track for block 2 is shorter

(d) d2 = d1, because the blocks start at the same height

(a) 0.40m (b) 1.0m (c) 2.5m (d) 10m (e) 25m

(e) 25m

(a) It increases only (b) It decreases only (c) It increases and then decreases (d) It decreases and then increases (e) It does not change

(a) It increases only

(a) 0 J (b) 1.4 J (c) 2.8 J (d) 4.7 J (e) 8.4 J

(d) 4.7 J

(a) mg (b) mh (c) mgh (d) mght (e) mgh / t

(a) U = -1/2 kx^2 (b) U = 1/2 kx^2 (c) U = -1/4 kx^4 (d) U = 1/4 kx^4 (e) U = -3kx^2

(d) U = 1/4 kx^4

(a) 2m/s (b) 4m/s (c) 20m/s (d) 40m/s (e) 200m/s

(a) 2m/s

(a) Rock A hits the ground with a greater speed than Rock B (b) Rock B hits the ground with a greater acceleration than Rock A (c) Rock A and Rock B hit the ground with the same speed (d) Rock A and Rock B hit the ground simultaneously (e) Rock B's acceleration changes direction during the flight

(a) 1/4 D (b) 1/2 D (c) 2D (d) 4D

(b) 1/2 D

Which of the following graphs best shows the sum of kinetic energy of the two blocks and potential energy U of the two-block Earth system, as a function of distance x Block A has moved along the horizontal surface before Block A reaches the pulley? (a) (b) (c) (d) (e)

(e)

(a) sqrt(gx) (b) sqrt(gx sintheta) (c) sqrt(2gx sintheta) (d) sqrt(gx(1 + sintheta)) (e) sqrt(2gx( 1 + sintheta))

(b) sqrt(gx sintheta)

(a) sqrt(2GM/3R) (b) sqrt(4GM/3R) (c) sqrt(8GM/3R) (d) sqrt(3GM/R) (e) sqrt(6GM/R)

(b) sqrt(4GM/3R)

(a) 6.9 degrees (b) 9.8 degrees (c) 10 degrees (d) 14 degrees (e) 19 degrees

(d) 14 degrees

Which of the following graphs could represent Ef as a function of mew? (a) (b) (c) (d)

(d)

(a) Friction between the bale and block 2 is not negligible. (b) The mass of block 2 is actually greater than the mass of block 1 (c) Air resistance is not negligible (d) There is friction between the rim of the pulley disk and the string (E) The table is not horizontal

(E) The table is not horizontal

(a) (sqrt(gh))/3 (b) (sqrt(gh))/2 (c) sqrt((2gh)/3)) (d) sqrt(gh) (e) sqrt((3gh)/2)

(a) The power delivered is constant (b) The power delivered is always positive (c) The power delivered is always negative (d) The power is positive then zero, then negative

(d) The power is positive then zero, then negative

(a) 10.5 W (b) 16.0 W (c) 17.0 W (d) 21.0 W

(a) (At) / t + B (b) (A) / (t + b)^2 (c) A ln(t + B) (d) A ln((t + B) / B)

(d) A ln((t + B) / B)

(a) 2P (b) Greater than P but less than 2P (c) P (d) Less than P but greater than P/2 (e) P/2

(b) Greater than P but less than 2P

(a) 0 W (b) 0.72 W (c) 3.0 W (d) 5.2 W

(a) 1/9 (b) 1/3 (c) 4/3 (d) 4/1

(a) 0.11 (b) 0.17 (c) 4 (d) 6 (e) 9

(e) 9

A box is pushed across a surface where friction between the box and the surface is negligible. There is a resistive force from the air exerted on the box equal to Fr = -kv. Which of the following graphs correctly models the relationship between the power P required to move the box at a constant speed v, as a function of the speed of the box? (a) curved up (b) straight up (c) horizontal line (d) curve down

(a) curved up

(a) A Increases and Decreases (b) B Increases and Remains the same (c) C Remains the same and Decreases (d) D Remains the same and Remains the same

(b) B Increases and Remains the same

(a) A W2 = W1 and t2 > t1 (b) B W2 > W1 and t2 = t1 (c) C W2 = W1 and t2 = t1 (d) D W2 > W1 and t2 > t1

(d) D W2 > W1 and t2 > t1

(a) 1.0m (b) 4.0m (c) 10m (d) 40m

4.0m

(a) Force up vi to the right (b) Force left vi to the right (c) Force right vi to the right (d) force upright vi to the right

(a) Mass of block = 1/2 m (b) Spring constant 1/2 k (c) Speed at equilibrium = 1/2 v (d) Kinetic energy at equilibrium = 1/2 K (e) Potential energy when block comes to rest after passing equilibrium = 1/2U

(d) Kinetic energy at equilibrium = 1/2 K

(a) W2 > W and t2 < t, because the more-powerful motor can do more work and do the work faster (b) W2 > W and t2 < t, because whenever the work done faster, more work will be done (c) W2 = W and t2 < t, because the object is lifted to the same height and the more-powerful motor can do work faster (d) W2 > W and t2 < t, because the object is lifted to the same height and the more-powerful motor can do work faster. (e) W2 = W and t2 = t, because the object is lifted to the same height, and the work done and the time to do the work will be the same.

(a) The two stones reach the ground at the same time with same speed (b) The two stones reach the ground at the same time but with different speeds (c) Stone A reaches the ground first, but the two stones have the same speed just before they hit the ground. (d) Stone A reaches the ground first and has greater speed just before hitting the ground.

(a) 0 (b) 1 (c) 3 (d) 4

(a) v^2 / 2g (b) v/sqrt(2g) (c) Mv^2 / 2mg (d) 2g / v^2 (e) 2g / v

(a) v^2 / 2g

(a) kx/4mg (b) kx/2mg (c) 3kx/4mg (d) kx/mg (e) 2kx/mg

(a) kx/4mg

(a) 0 (b) kx/2 (c) kx^2 / 2 - (mew)mgx (d) kx^2 / 2 - 3(mew)mgx / 2 (e) kx^2 /2 - 2(mew)mgx

(a) 0W (b) 1 / pi (c) 16 W (d) 16pi W

(d) 16pi W

If the plane is frictionless, what speed v_cm of the center of mass of the sphere at the bottom of the incline? (a) sqrt(2gh) (b) 2Mgh / I (c) 2Mghr^2 / I (d) sqrt(2Mghr^2 / I ) (e) sqrt(2Mghr^2 / I + Mr^2 )

(a) sqrt(2gh)

If the plane has friction so that the sphere rolls without slipping, what is the speed of the v_cm of the center of mass at the bottom of the incline. (a) sqrt(2gh) (b) 2Mgh / I (c) 2Mghr^2 / I (d) sqrt(2Mghr^2 / I ) (e) sqrt(2Mghr^2 / I + Mr^2 )

(e) sqrt(2Mghr^2 / I + Mr^2 )

(a) 3b/2 r^-5/2 (b) 3b/2 r^-1/2 (c) 3/2r ^-1/2 (d) 2br^-1/2 + cr (e) 2b/5r^-5/2 + cr

(a) 3b/2 r^-5/2

(a) sqrt(8U / m) (b) sqrt(6U / m) (c) sqrt(4U / m) (d) sqrt(2U / m) (e) sqrt(U / m)

(a) The kinetic energy of the object is approximately the same at x = 2m and x = 5m. (b) At x = 2m, the object has more potential energy than kinetic energy (c) The object comes to rest when x = 5.5m (d) The rate of change of the potential energy is a minimum at x = 0m (e) The object achieves its maximum speed at approximately x = 3m

(e) The object achieves its maximum speed at approximately x = 3m

(a) The total mechanical energy of the system is conserved. (b) The total mechanical energy of the system increases (c) The energy lost to friction is equal to the gain in the potential energy of the spring. (d) the potential energy lost by block 2 is less in magnitude than the potential energy gained by the spring (e) The potential energy lost by block 2 is greater in magnitude than the potential energy gained by the spring

(e) The potential energy lost by block 2 is greater in magnitude than the potential energy gained by the spring

(a) 4.0 * 10^5 J (b) 5.2 * 10^5 J (c) 9.0 * 10^5 J (d) 14.0 x 10^5 J

(a) 20 J (b) 40 J (c) 60 J (d) 80 J

(b) 40 J

(a) Kinetic energy only because block 1 is moving relative to block 2 (b) Kinetic energy only because block 1 is in motion but has no internal parts that can interact with each other (c) Kinetic energy and elastic potential energy because both blocks are in motion and the spring length is changing (d) Kinetic energy and elastic potential energy because bock 1 is in motion and the spring exerts an external force on it.

(b) Kinetic energy only because block 1 is in motion but has no internal parts that can interact with each other

(a) Its rotational kinetic energy equals the initial potential energy of the sphere-Earth system. (b) Its translational kinetic energy equals the initial potential energy of the sphere-Earth system. (c) Its translational kinetic energy and rotational kinetic energy and rotational kinetic energy are equal (d) The sum of its translational kinetic energy and rotational kinetic energy equals the initial potential energy of the sphere-Earth system. (e) The sum of its translational kinetic energy and rotational kinetic energy equals the energy lost because of friction

(d) The sum of its translational kinetic energy and rotational kinetic energy equals the initial potential energy of the sphere-Earth system.

(a) 1.0m (b) 5.0 m (c) 10m (d) 25m

(d) 25m

(a) 0.5 J (b) 1 J (c) 2 J (d) 4 J (e) infinity

(b) 1 J

(a) 16 N (b) 8 N (c) 6 N (d) 4 N (e) 2 N

(e) 2 N

(a) 2mg / k (b) mg / k (c) mg sintheta / k (d) 2mg sintheta / k (e) sqrt(mgsintheta / k )

(d) 2mg sintheta / k

(a) e = 1/2 KX^2 + 1/2 mv^2 (b) e = 1/2 kx^2 - 1/2mv^2 (c) e = 1/2k(D - x)^2 + 1/2 mv^2 (d) e = 1/2k(D - x)^2 - 1/2 mv^2

(b) e = 1/2 kx^2 - 1/2mv^2

(a) E1 < E2 (b) E1 = E2 (c) E1 > E2 (d) The comparison cannot be made without knowing the relative values of the block masses and spring constants of the springs.

(d) The comparison cannot be made without knowing the relative values of the block masses and spring constants of the springs.

(a) A less and Less (b) B Less and Same (c) C Greater and Less (d) D Greater and Same

(a) A vA = vB and Ea > Eb (b) B vA = vB and Ea < Eb (c) vA > vB and Ea = Eb (d) vA < vB and Ea = Eb

(a) A vA = vB and Ea > Eb

(a) vA = vB = vC (b) vB < vA = vC (c) vA = vB = vC (d) vB < vA < vC

(d) vB < vA < vC

(a) 3/4d (b) 4/5d (c) sqrt(3) / 2d (d) 2 / sqrt(5) d

(d) 2 / sqrt(5) d

(a) In the block only system, the total energy increases because the net work done on the box is greater than zero (b) In the block only system, the total energy remains constant because energy is dissipated by friction (c) In the block-Earth system, the total energy increases because the force of gravity does more work on the block than is dissipated by the force of friction exerted on the block. (d) In the block-Earth system, the total energy remains constant because energy is always conserved

(a) In the block only system, the total energy increases because the net work done on the box is greater than zero

(a) kx^2 / mgsintheta (b) kx^2 / 2mgsintheta (c) (kx^2 + 2mgxsintheta) / 2mgsintheta (d) (kx^2 - 2mgxsintheta) / 2mgsintheta

(b) kx^2 / 2mgsintheta

(a) h0 = h1 = h2, because mechanical energy is conserved (b) h0 = h1 = h2, because the maximum height of the block is always equal to the initial height from which the block is released. (c) h0 > h2 > h1, because the increasing angle at which the block leaves the incline decreases the kinetic energy of the block when it is at its maximum height (d) h0 > h2 > h1, because increasing the angle at which the block leaves the incline increases the amount of work the incline does on the block

(c) h0 > h2 > h1, because the increasing angle at which the block leaves the incline decreases the kinetic energy of the block when it is at its maximum height

A motor is used to life a platform as shown between times t = 0 and t = 3s. The power supplied by the motor is given by P = A - Bt, where A = 6 W and B = 2 W/s. Which of the following graphs could represent the work done on the platform by the motor as a function of time? (a) (b) (c) (d)

(d)

(a) 24 kJ (b) 30 kJ (c) 36 kJ (d) 42 kJ (e) 48 kJ

(d) 42 kJ

(a) Iw/2T (b) Iw^2 / 2T (c) Iw^2 / 2T^2 (d) I^2 w/2T^2 (e) I^2 w^2 / 2T^2

(b) Iw^2 / 2T

(a) 24 W (b) 40 W (c) 64 W (d) 88 W

64 W

(a) Sphere X only (b) Sphere Y only (c) Sphere Z only (d) Spheres X and Z only (e) All three spheres collide with the same speed

(e) All three spheres collide with the same speed

(a) X > Y > Z (b) Y > (X = Z) (c) Z > Y > X (d) (X = Y) > Z (e) (X = Z) > Y

(e) (X = Z) > Y

(a) 0.25s (b) 0.40s (c) 1.0s (d) 2.0s (e) 4.0s

(e) 4.0s

(a) 3.3J (b) 5 J (c) 6.7 J (d) 10 J (e) 15 J

(b) 5 J

(a) 2.5 J (b) 10 J (c) 20 J (d) 30 J (e) 40 J

(e) 40 J

(a) 6 * 10^ 3 W (b) 2 * 10^4 W (c) 3 * 10^ 4 W (d) 4 * 10^4 W (e) 6 * 10^4 W

(e) 6 * 10^4 W

(a) 1m (b) 3m (c) 10m (d) 32m (e) 100m

Unit 3 Test Flashcards

(104 cards)