Question 1

A baseball is thrown and lands 120 m away.While the ball is in flight,assuming the effect of air friction is negligible,which of the following is true?

Accepted Answer

A) At maximum height the ball has its greatest kinetic energy. 
B) The horizontal component of the baseball's kinetic energy is constant. 
C) The vertical component of the baseball's kinetic energy is constant. 
D) The mechanical energy of the baseball is greater when nearer to the ground. 
E) No answer above is correct. 
A) At maximum height the ball has its greatest kinetic energy. 
B) The horizontal component of the baseball's kinetic energy is constant. 
C) The vertical component of the baseball's kinetic energy is constant. 
D) The mechanical energy of the baseball is greater when nearer to the ground. 
E) No answer above is correct.

Question 2

Each of two vectors, $\overrightarrow { \mathrm { D } } _ { 1 }$ and $\overrightarrow { \mathrm { D } } _ { 2 }$ ,lies along a coordinate axis in the xy plane.Each vector has its tail at the origin,and the dot product of the two vectors is $\overrightarrow { \mathrm { D } } _ { 1 } \cdot \overrightarrow { \mathrm { D } } _ { 2 } = 0$ .Which possibility is correct?

Accepted Answer

A)  $\overrightarrow { \mathrm { D } } _ { 1 }$ and $\overrightarrow { \mathrm { D } } _ { 2 }$ both lie along the positive x axis. 
B)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the positive x axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative x axis. 
C)  $\overrightarrow { \mathrm { D } } _ { 1 }$ and $\overrightarrow { \mathrm { D } } _ { 2 }$ both lie along the positive y axis. 
D)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the negative x axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative y axis. 
E)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the positive y axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative y axis. 
A)  $\overrightarrow { \mathrm { D } } _ { 1 }$ and $\overrightarrow { \mathrm { D } } _ { 2 }$ both lie along the positive x axis. 
B)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the positive x axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative x axis. 
C)  $\overrightarrow { \mathrm { D } } _ { 1 }$ and $\overrightarrow { \mathrm { D } } _ { 2 }$ both lie along the positive y axis. 
D)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the negative x axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative y axis. 
E)  $\overrightarrow { \mathrm { D } } _ { 1 }$ lies along the positive y axis. $\overrightarrow { \mathrm { D } } _ { 2 }$ lies along the negative y axis.

Question 3

As a 2.0-kg object moves from $( 2 \tilde { \mathbf { i } } + 5 \tilde { \mathbf { j } } )$ m to $( 6 \tilde { \mathbf { i } } - 2 \tilde { \mathbf { j } } )$ m,the constant resultant force acting on it is equal to $( 4 \tilde { \mathbf { i } } - 3 \tilde { \mathbf { j } } )$ N.If the speed of the object at the initial position is 4.0 m/s,what is its kinetic energy at its final position?

Accepted Answer

A) 62 J 
B) 53 J 
C) 73 J 
D) 86 J 
E) 24 J 
A) 62 J 
B) 53 J 
C) 73 J 
D) 86 J 
E) 24 J

Question 4

A 0.40-kg particle moves under the influence of a single conservative force.At point A where the particle has a speed of 10 m/s,the potential energy associated with the conservative force is +40 J.As the particle moves from A to B,the force does +25 J of work on the particle.What is the value of the potential energy at point B?

Accepted Answer

A) +65 J 
B) +15 J 
C) +35 J 
D) +45 J 
E) -40 J 
A) +65 J 
B) +15 J 
C) +35 J 
D) +45 J 
E) -40 J

Question 5

A 7.0-kg block on a horizontal frictionless surface is attached to a light spring (force constant = 1.2 kN/m).The block is initially at rest at its equilibrium position when a force of magnitude P acting parallel to the surface is applied to the block,as shown.When the block is 8.0 cm from the equilibrium position,it has a speed of 0.80 m/s.How much work is done on the block by the force P as the block moves the 8.0 cm?

Accepted Answer

A) 7.4 J 
B) 5.4 J 
C) 6.1 J 
D) 6.7 J 
E) 4.9 J 
A) 7.4 J 
B) 5.4 J 
C) 6.1 J 
D) 6.7 J 
E) 4.9 J

Question 6

A 3.0-kg block is dragged over a rough horizontal surface by a constant force of 16 N acting at an angle of 37$\degree$ above the horizontal as shown.The speed of the block increases from 4.0 m/s to 6.0 m/s in a displacement of 5.0 m.What work was done by the friction force during this displacement?

Accepted Answer

A) -34 J 
B) -64 J 
C) -30 J 
D) -94 J 
E) +64 J 
A) -34 J 
B) -64 J 
C) -30 J 
D) -94 J 
E) +64 J

Question 7

A moving particle is subject to conservative forces only.When its kinetic energy decreases by 10 J,what happens to its mechanical energy?

Accepted Answer

A) It increases by 10 J. 
B) It decreases by 10 J. 
C) It increases,but not necessarily by 10 J. 
D) It decreases,but not necessarily by 10 J. 
E) It remains the same. 
A) It increases by 10 J. 
B) It decreases by 10 J. 
C) It increases,but not necessarily by 10 J. 
D) It decreases,but not necessarily by 10 J. 
E) It remains the same.

Question 8

If $\overrightarrow { \mathrm { A } }$ = 10, $\vec { B }$ = 15,and $\alpha$ = 130$\degree$,determine the scalar product of the two vectors shown.

Accepted Answer

A) +96 
B) -96 
C) +51 
D) -51 
E) -35 
A) +96 
B) -96 
C) +51 
D) -51 
E) -35

Question 9

A 10-kg block on a rough horizontal surface is attached to a light spring (force constant = 1.4 kN/m).The block is pulled 8.0 cm to the right from its equilibrium position and released from rest.The frictional force between the block and surface has a magnitude of 30 N.What is the kinetic energy of the block as it passes through its equilibrium position?

Accepted Answer

A) 4.5 J 
B) 2.1 J 
C) 6.9 J 
D) 6.6 J 
E) 4.9 J 
A) 4.5 J 
B) 2.1 J 
C) 6.9 J 
D) 6.6 J 
E) 4.9 J

Question 10

A 2.0-kg particle has an initial velocity of $( 5 \tilde { \mathbf { i } } - 4 \tilde { \mathbf { j } } )$ m/s.Some time later,its velocity is $7 \tilde { \mathbf { i } } + 3 \tilde { \mathbf { j } }$ m/s.How much work was done by the resultant force during this time interval,assuming no energy is lost in the process?

Accepted Answer

A) 17 J 
B) 49 J 
C) 19 J 
D) 53 J 
E) 27 J 
A) 17 J 
B) 49 J 
C) 19 J 
D) 53 J 
E) 27 J

Question 11

In a contest,two tractors pull two identical blocks of stone the same distance over identical surfaces.However,block A is moving twice as fast as block B when it crosses the finish line.Which statement is correct?

Accepted Answer

A) Block A has twice as much kinetic energy as block B. 
B) Block B has lost twice as much kinetic energy to friction as block A. 
C) Block B has lost twice as much kinetic energy as block A. 
D) Both blocks have had equal losses of energy to friction. 
E) No energy is lost to friction because the ground has no displacement. 
A) Block A has twice as much kinetic energy as block B. 
B) Block B has lost twice as much kinetic energy to friction as block A. 
C) Block B has lost twice as much kinetic energy as block A. 
D) Both blocks have had equal losses of energy to friction. 
E) No energy is lost to friction because the ground has no displacement.

Question 12

A constant force of 15 N in the negative y direction acts on a particle as it moves from the origin to the point $( 3 \hat{ \mathbf { i } } + 3 \hat { \mathbf { j } } - 1 \hat { \mathbf { k } } )$ m.How much work is done by the given force during this displacement?

Accepted Answer

A) +45 J 
B) -45 J 
C) +30 J 
D) -30 J 
E) +75 J 
A) +45 J 
B) -45 J 
C) +30 J 
D) -30 J 
E) +75 J

Question 13

If the scalar product of two vectors, $\overrightarrow { \mathrm { A } }$ and $\overrightarrow { \mathrm { C } }$ ,is equal to -3.5,if $| \overrightarrow { \mathbf { A } } | = 2.0$ ,and the angle between the two vectors when they are drawn starting from the same point is equal to 130$\degree$,what is the magnitude of $\overrightarrow { \mathrm { C } }$ ?

Accepted Answer

A) 2.1 
B) 2.5 
C) 2.3 
D) 2.7 
E) 3.1 
A) 2.1 
B) 2.5 
C) 2.3 
D) 2.7 
E) 3.1

Question 14

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30$\degree$.What is the kinetic energy of the baseball at the highest point of the trajectory?

Accepted Answer

The answer of A baseball outfielder throws a baseball of...

Question 15

Two eggs of equal mass are thrown at a blanket with equal velocity.Egg B hits the blanket but egg A hits the wall instead.Compare the work done on the eggs in reducing their velocities to zero.

Accepted Answer

A) More work was done on A than on B. 
B) More work was done on B than on A. 
C) The amount of work is the same for both. 
D) It is meaningless to compare the amount of work because the forces were so different. 
E) Work was done on B,but no work was done on A because the wall did not move. 
A) More work was done on A than on B. 
B) More work was done on B than on A. 
C) The amount of work is the same for both. 
D) It is meaningless to compare the amount of work because the forces were so different. 
E) Work was done on B,but no work was done on A because the wall did not move.

Question 16

Carts A and B have equal masses and travel equal distances on straight frictionless tracks while a constant force F is applied to A,and a constant force 2F is applied to B.The relative amounts of work done by the two forces are related by

Accepted Answer

A) WA = 4 WB. 
B) WA = 2 WB. 
C) WA = WB. 
D) WB = 2 WA. 
E) WB = 4 WA. 
A) WA = 4 WB. 
B) WA = 2 WB. 
C) WA = WB. 
D) WB = 2 WA. 
E) WB = 4 WA.

Question 17

A 10-kg block on a horizontal frictionless surface is attached to a light spring (force constant = 1.2 kN/m).The block is initially at rest at its equilibrium position when a force (magnitude P)acting parallel to the surface is applied to the block,as shown.When the block is 8.0 cm from the equilibrium position,it has a speed of 0.80 m/s.How much work is done on the block by the force P as the block moves the 8.0 cm?

Accepted Answer

A) 8.3 J 
B) 6.4 J 
C) 7.0 J 
D) 7.7 J 
E) 3.9 J 
A) 8.3 J 
B) 6.4 J 
C) 7.0 J 
D) 7.7 J 
E) 3.9 J

Question 18

After a skydiver reaches terminal velocity,

Accepted Answer

A) the force of gravity no longer performs work on the skydiver. 
B) work performed by the force of gravity is converted into gravitational potential energy. 
C) gravitational potential energy is no longer available to the system of the skydiver plus the Earth. 
D) gravitational potential energy is converted into thermal energy. 
E) thermal energy is converted into gravitational potential energy. 
A) the force of gravity no longer performs work on the skydiver. 
B) work performed by the force of gravity is converted into gravitational potential energy. 
C) gravitational potential energy is no longer available to the system of the skydiver plus the Earth. 
D) gravitational potential energy is converted into thermal energy. 
E) thermal energy is converted into gravitational potential energy.

Question 19

A 20-kg block on a horizontal surface is attached to a light spring (force constant = 8.0 kN/m).The block is pulled 10 cm to the right from its equilibrium position and released from rest.When the block has moved 2.0 cm toward its equilibrium position,its kinetic energy is 13 J.How much work is done by the frictional force on the block as it moves the 2.0 cm?

Accepted Answer

A) -2.5 J 
B) -1.4 J 
C) -3.0 J 
D) -1.9 J 
E) -14 J 
A) -2.5 J 
B) -1.4 J 
C) -3.0 J 
D) -1.9 J 
E) -14 J

Question 20

A single conservative force Fx = (6.0x - 12)N (x is in m)acts on a particle moving along the x axis.The potential energy associated with this force is assigned a value of +20 J at x = 0.What is the potential energy at x = 3.0 m?

Accepted Answer

A) +11 J 
B) +29 J 
C) +9.0 J 
D) -9.0 J 
E) +20 J 
A) +11 J 
B) +29 J 
C) +9.0 J 
D) -9.0 J 
E) +20 J

Exam 6: Energy of a System

A baseball is thrown and lands 120 m away.While the ball is in flight,assuming the effect of air friction is negligible,which of the following is true?

A moving particle is subject to conservative forces only.When its kinetic energy decreases by 10 J,what happens to its mechanical energy?

If A→\overrightarrow { \mathrm { A } }A = 10, B⃗\vec { B }B = 15,and α\alphaα = 130 °\degree° ,determine the scalar product of the two vectors shown.

In a contest,two tractors pull two identical blocks of stone the same distance over identical surfaces.However,block A is moving twice as fast as block B when it crosses the finish line.Which statement is correct?

A constant force of 15 N in the negative y direction acts on a particle as it moves from the origin to the point (3i^+3j^−1k^)( 3 \hat{ \mathbf { i } } + 3 \hat { \mathbf { j } } - 1 \hat { \mathbf { k } } )(3i^+3j^​−1k^) m.How much work is done by the given force during this displacement?

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30 °\degree° .What is the kinetic energy of the baseball at the highest point of the trajectory?

Two eggs of equal mass are thrown at a blanket with equal velocity.Egg B hits the blanket but egg A hits the wall instead.Compare the work done on the eggs in reducing their velocities to zero.

Carts A and B have equal masses and travel equal distances on straight frictionless tracks while a constant force F is applied to A,and a constant force 2F is applied to B.The relative amounts of work done by the two forces are related by

After a skydiver reaches terminal velocity,

A single conservative force Fx = (6.0x - 12)N (x is in m)acts on a particle moving along the x axis.The potential energy associated with this force is assigned a value of +20 J at x = 0.What is the potential energy at x = 3.0 m?

Introduction and Vectors

Motion in One Dimension

Motion in Two Dimensions

The Laws of Motion

More Applications of Newtons Laws

Conservation of Energy

Momentum and Collisions

Relativity

Rotational Motion

Gravity,planetary Orbits,and the Hydrogen Atom

Oscillatory Motion

Mechanical Waves

Superposition and Standing Waves

Fluid Mechanics

Temperature and the Kinetic Theory of Gases

Energy in Thermal Processes: the First Law of Thermodynamics

Heat Engines,entropy,and the Second Law of Thermodynamics

Electric Forces and Electric Fields

Electric Potential and Capacitance

Current and Direct Current Circuits

Magnetic Forces and Magnetic Fields

Faradays Law and Inductance

Electromagnetic Waves

Reflection and Refraction of Light

Image Formation by Mirrors and Lenses

Wave Optics

Quantum Physics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

If $\overrightarrow { \mathrm { A } }$ = 10, $\vec { B }$ = 15,and $\alpha$ = 130 $\degree$ ,determine the scalar product of the two vectors shown. $If \overrightarrow { \mathrm { A } } = 10, \vec { B } = 15,and \alpha = 130 \degree ,determine the scalar product of the two vectors shown.$

A constant force of 15 N in the negative y direction acts on a particle as it moves from the origin to the point $( 3 \hat{ \mathbf { i } } + 3 \hat { \mathbf { j } } - 1 \hat { \mathbf { k } } )$ m.How much work is done by the given force during this displacement?

A baseball outfielder throws a baseball of mass 0.15 kg at a speed of 40 m/s and initial angle of 30 $\degree$ .What is the kinetic energy of the baseball at the highest point of the trajectory?

A single conservative force F_x = (6.0x - 12)N (x is in m)acts on a particle moving along the x axis.The potential energy associated with this force is assigned a value of +20 J at x = 0.What is the potential energy at x = 3.0 m?