Question 1

Two identical springs with spring constant 50 N/m support a 5.0 N weight as in the picture below. What is the tension in spring A?

Accepted Answer

A) 1.45 N 
B) 2.50 N 
C) 2.89 N 
D) 3.75 N 
E) 5.00 N 
A) 1.45 N 
B) 2.50 N 
C) 2.89 N 
D) 3.75 N 
E) 5.00 N

Question 2

A 1.5-kg object has a velocity of 5 $\hat{\mathbf{j}}$ m/s at t = 0. It is accelerated at a constant rate for five seconds after which it has a velocity of (6 $\hat{\mathbf{i}}$ + 12 $\hat{\mathbf{j}}$ ) m/s. What is the magnitude of the resultant force acting on the object during this time interval?

Accepted Answer

A) 3.8 N 
B) 3.2 N 
C) 2.8 N 
D) 4.3 N 
E) 4.6 N 
A) 3.8 N 
B) 3.2 N 
C) 2.8 N 
D) 4.3 N 
E) 4.6 N

Question 3

When you drag a toy teddy bear along the floor by a force that is parallel to the floor, the magnitude of the force of friction:

Accepted Answer

A) is independent of velocity or acceleration. 
B) increases when the velocity increases. 
C) is proportional to the acceleration. 
D) decreases when the force parallel to the floor increases. 
E) increases when the force parallel to the floor increases. 
A) is independent of velocity or acceleration. 
B) increases when the velocity increases. 
C) is proportional to the acceleration. 
D) decreases when the force parallel to the floor increases. 
E) increases when the force parallel to the floor increases.

Question 4

A heavy weight is supported by two cables that exert tensions of magnitude T1 and T2. Which statement is correct?

Accepted Answer

A) T1 = T2. B) T1y = T2y. C) T1 > T2. D) T1 < T2. E) We need the mass of the box in order to determine the correct answer. A) T1 = T2. B) T1y = T2y. C) T1 > T2. D) T1 < T2. E) We need the mass of the box in order to determine the correct answer.

Question 5

A constant force F is applied to a body of mass m that initially is headed east at velocity v0 until its velocity becomes -v0. The total time of travel is 2t. The total distance the body travels in that time is:

Accepted Answer

A)  $\frac{1}{2} \frac{F}{m} t^{2}$ . 
B)  $\frac{F}{m} t^{2}$ . 
C)  $v_{0} t-\frac{1}{2} \frac{F}{m} t^{2}$ . 
D)  $v_{0} t+\frac{1}{2} \frac{F}{m} t^{2}$ . 
E)  $2\left(v_{0} t+\frac{1}{2} \frac{F}{m} t^{2}\right)$ . 
A)  $\frac{1}{2} \frac{F}{m} t^{2}$ . 
B)  $\frac{F}{m} t^{2}$ . 
C)  $v_{0} t-\frac{1}{2} \frac{F}{m} t^{2}$ . 
D)  $v_{0} t+\frac{1}{2} \frac{F}{m} t^{2}$ . 
E)  $2\left(v_{0} t+\frac{1}{2} \frac{F}{m} t^{2}\right)$ .

Question 6

Two bodies, A and B, collide as shown in Figures I and II below.   Which statement is true?

Accepted Answer

A) They exert equal and opposite forces on each other in I but not in II. 
B) They exert equal and opposite force on each other in II but not in I. 
C) They exert equal and opposite force on each other in both I and II. 
D) The forces are equal and opposite to each other in I, but only the components of the forces parallel to the velocities are equal in II. 
E) The forces are equal and opposite in I, but only the components of the forces perpendicular to the velocities are equal in II 
A) They exert equal and opposite forces on each other in I but not in II. 
B) They exert equal and opposite force on each other in II but not in I. 
C) They exert equal and opposite force on each other in both I and II. 
D) The forces are equal and opposite to each other in I, but only the components of the forces parallel to the velocities are equal in II. 
E) The forces are equal and opposite in I, but only the components of the forces perpendicular to the velocities are equal in II

Question 7

If the tension, T, is 15 N and the magnitude of the acceleration, a, is 3.0 m/s2, what is the mass, m, of the suspended object? Assume that all surfaces and the pulley are frictionless.

Accepted Answer

A) 3.1 kg 
B) 2.5 kg 
C) 2.8 kg 
D) 2.2 kg 
E) 3.7 kg 
A) 3.1 kg 
B) 2.5 kg 
C) 2.8 kg 
D) 2.2 kg 
E) 3.7 kg

Question 8

When the vector sum of three co-planar forces, $\vec{A}$ , $\overrightarrow{\mathbf{B}}$ and $\overrightarrow{\mathbf{C}}$ , is parallel to $\vec{A}$ , we can conclude that $\overrightarrow{\mathbf{B}}$ and $\overrightarrow{\mathbf{C}}$ :

Accepted Answer

A) must sum to zero. 
B) must be equal and opposite. 
C) must have equal and opposite components perpendicular to $\vec{A}$ . 
D) must have equal and opposite components parallel to $\vec{A}$ . 
E) must have equal and opposite components parallel and perpendicular to $\vec{A}$ . 
A) must sum to zero. 
B) must be equal and opposite. 
C) must have equal and opposite components perpendicular to $\vec{A}$ . 
D) must have equal and opposite components parallel to $\vec{A}$ . 
E) must have equal and opposite components parallel and perpendicular to $\vec{A}$ .

Question 9

If $\alpha$ = 40$\degree$ and the tension in string 2 is 30 N, determine M.

Accepted Answer

A) 3.4 kg 
B) 3.6 kg 
C) 2.6 kg 
D) 4.9 kg 
E) 7.5 kg 
A) 3.4 kg 
B) 3.6 kg 
C) 2.6 kg 
D) 4.9 kg 
E) 7.5 kg

Question 10

Three boxes slide on a frictionless horizontal surface when pulled by a force of magnitude F. When we compare the tensions T1 and T2 with the force F, we find that

Accepted Answer

A) T1 = T2 = F. B) T1 = F > T2. C) F > T1 = T2. D) F > T1 > T2. E) F - T1 < T1 - T2. A) T1 = T2 = F. B) T1 = F > T2. C) F > T1 = T2. D) F > T1 > T2. E) F - T1 < T1 - T2.

Question 11

If M = 2.0 kg, what is the tension in string 1?

Accepted Answer

A) 1.2 N 
B) 11 N 
C) 34 N 
D) 3.5 N 
E) 40 N 
A) 1.2 N 
B) 11 N 
C) 34 N 
D) 3.5 N 
E) 40 N

Question 12

Given the equation $(2.00 \mathrm{~kg})\left(5.00 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}\right)=20.00 \mathrm{~N}-10.00 \mathrm{~N}$ , which answer or answers provide(s) the best description of a possible physical situation?

Accepted Answer

A) A 20.00 N tension pulls a 2.00 kg mass. The 2.00 kg mass pulls another 2.00 kg mass. 
B) A 20.00 N force pushes a 2.00 kg mass. The 2.00 kg mass pushes another 2.00 kg mass. 
C) A 2.00 kg mass on a flat surface is acted on by gravity while another 2.00 kg mass sits on top of it. 
D) All of the situations above are possible. 
E) Only (a) and (b) above are possible. 
A) A 20.00 N tension pulls a 2.00 kg mass. The 2.00 kg mass pulls another 2.00 kg mass. 
B) A 20.00 N force pushes a 2.00 kg mass. The 2.00 kg mass pushes another 2.00 kg mass. 
C) A 2.00 kg mass on a flat surface is acted on by gravity while another 2.00 kg mass sits on top of it. 
D) All of the situations above are possible. 
E) Only (a) and (b) above are possible.

Question 13

A book is placed on a chair. Then a videocassette is placed on the book. The floor exerts a normal force:

Accepted Answer

A) on all three. 
B) only on the book. 
C) only on the chair. 
D) upwards on the chair and downwards on the book. 
E) only on the objects that you have defined to be part of the system. 
A) on all three. 
B) only on the book. 
C) only on the chair. 
D) upwards on the chair and downwards on the book. 
E) only on the objects that you have defined to be part of the system.

Question 14

A 70-kg stunt artist rides in a rocket sled which slides along a flat inclined surface. At an instant when the sled's acceleration has a horizontal component of 6.0 m/s2 and a downward component of 2.8 m/s2, what is the magnitude of the force on the rider by the sled?

Accepted Answer

A) 0.83 kN 
B) 0.98 kN 
C) 0.65 kN 
D) 0.68 kN 
E) 0.72 kN 
A) 0.83 kN 
B) 0.98 kN 
C) 0.65 kN 
D) 0.68 kN 
E) 0.72 kN

Question 15

A 2000-kg sailboat heading out to sea through the Sydney heads experiences an eastward force of 3000 N by the ocean tide and a wind force against its sails of magnitude 6000 N directed toward the northwest (45$\degree$ N of W). What is the magnitude and direction of the resultant acceleration?

Accepted Answer

2.2 m/s2 a

Question 16

The apparent weight of a fish in an elevator is greatest when the elevator:

Accepted Answer

A) moves downward at constant velocity. 
B) moves upward at constant velocity. 
C) accelerates downward. 
D) accelerates upward. 
E) is not moving. 
A) moves downward at constant velocity. 
B) moves upward at constant velocity. 
C) accelerates downward. 
D) accelerates upward. 
E) is not moving.

Question 17

If F = 40 N and M = 1.5 kg, what is the tension in the string connecting M and 2M? Assume that all surfaces are frictionless.

Accepted Answer

A) 13 N 
B) 23 N 
C) 36 N 
D) 15 N 
E) 28 N 
A) 13 N 
B) 23 N 
C) 36 N 
D) 15 N 
E) 28 N

Question 18

A juggler throws two balls up to the same height so that they pass each other halfway up when A is rising and B is descending. Ignore air resistance and buoyant forces. Which statement is true of the two balls at that point?

Accepted Answer

A) There is a residual upward force from the hand on each ball. 
B) There is a greater residual force from the hand on A than there is on B. 
C) Only gravity acts on B but there is an additional residual force from the hand on A. 
D) There is an additional downwards force besides gravity on each ball. 
E) The only force acting on each ball is the gravitational force. 
A) There is a residual upward force from the hand on each ball. 
B) There is a greater residual force from the hand on A than there is on B. 
C) Only gravity acts on B but there is an additional residual force from the hand on A. 
D) There is an additional downwards force besides gravity on each ball. 
E) The only force acting on each ball is the gravitational force.

Question 19

If M = 1.1 kg, what is the tension in string 1?

Accepted Answer

A) 54 N 
B) 47 N 
C) 40 N 
D) 62 N 
E) 57 N 
A) 54 N 
B) 47 N 
C) 40 N 
D) 62 N 
E) 57 N

Question 20

Three boxes are pushed across a frictionless horizontal surface as shown. When we compare the normal force N2,5 that mass 2m exerts on mass 5m with the normal force N5,10 that mass 5m exerts on mass 10m, we find that:

Accepted Answer

A) N2,5 = N5,10 = F. 
B) N2,5 = F > N5,10. 
C) F > N2,5 = N5,10. 
D) F > N2,5 > N5,10. 
E) F > N5,10 > N2,5. 
A) N2,5 = N5,10 = F. 
B) N2,5 = F > N5,10. 
C) F > N2,5 = N5,10. 
D) F > N2,5 > N5,10. 
E) F > N5,10 > N2,5.

Exam 4: Forces and Newtons Laws

Two identical springs with spring constant 50 N/m support a 5.0 N weight as in the picture below. What is the tension in spring A?

When you drag a toy teddy bear along the floor by a force that is parallel to the floor, the magnitude of the force of friction:

A heavy weight is supported by two cables that exert tensions of magnitude T1 and T2. Which statement is correct?

A constant force F is applied to a body of mass m that initially is headed east at velocity v0 until its velocity becomes -v0. The total time of travel is 2t. The total distance the body travels in that time is:

Two bodies, A and B, collide as shown in Figures I and II below. Which statement is true?

If the tension, T, is 15 N and the magnitude of the acceleration, a, is 3.0 m/s2, what is the mass, m, of the suspended object? Assume that all surfaces and the pulley are frictionless.

When the vector sum of three co-planar forces, A⃗\vec{A}A , B→\overrightarrow{\mathbf{B}}B and C→\overrightarrow{\mathbf{C}}C , is parallel to A⃗\vec{A}A , we can conclude that B→\overrightarrow{\mathbf{B}}B and C→\overrightarrow{\mathbf{C}}C :

If α\alphaα = 40 °\degree° and the tension in string 2 is 30 N, determine M.

Three boxes slide on a frictionless horizontal surface when pulled by a force of magnitude F. When we compare the tensions T1 and T2 with the force F, we find that

If M = 2.0 kg, what is the tension in string 1?

Given the equation (2.00 kg)(5.00 m s2)=20.00 N−10.00 N(2.00 \mathrm{~kg})\left(5.00 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}\right)=20.00 \mathrm{~N}-10.00 \mathrm{~N}(2.00 kg)(5.00 s2 m​)=20.00 N−10.00 N , which answer or answers provide(s) the best description of a possible physical situation?

A book is placed on a chair. Then a videocassette is placed on the book. The floor exerts a normal force:

A 70-kg stunt artist rides in a rocket sled which slides along a flat inclined surface. At an instant when the sled's acceleration has a horizontal component of 6.0 m/s2 and a downward component of 2.8 m/s2, what is the magnitude of the force on the rider by the sled?

A 2000-kg sailboat heading out to sea through the Sydney heads experiences an eastward force of 3000 N by the ocean tide and a wind force against its sails of magnitude 6000 N directed toward the northwest (45 °\degree° N of W). What is the magnitude and direction of the resultant acceleration?

The apparent weight of a fish in an elevator is greatest when the elevator:

If F = 40 N and M = 1.5 kg, what is the tension in the string connecting M and 2M? Assume that all surfaces are frictionless.

A juggler throws two balls up to the same height so that they pass each other halfway up when A is rising and B is descending. Ignore air resistance and buoyant forces. Which statement is true of the two balls at that point?

If M = 1.1 kg, what is the tension in string 1?

Three boxes are pushed across a frictionless horizontal surface as shown. When we compare the normal force N2,5 that mass 2m exerts on mass 5m with the normal force N5,10 that mass 5m exerts on mass 10m, we find that:

Physics and Measurement

Motion in One Dimension

Motion in Two Dimensions

Further Applications of Newtons Laws

Work, Force and Energy

Conservation of Energy

Linear Momentum and Collisions

Rotational Motion

Energy and Momentum in Rotating Systems

Gravity

Special Relativity

Fluid Statics

Fluid Dynamics

Solids

Oscillatory Motion

Wave Motion

Superposition and Interference

Heat and Temperature

Energy Transfer Processes and Thermodynamics

The Kinetic Theory of Gases

The Second Law of Thermodynamics, Heat Engines and Entropy

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When the vector sum of three co-planar forces, $\vec{A}$ , $\overrightarrow{\mathbf{B}}$ and $\overrightarrow{\mathbf{C}}$ , is parallel to $\vec{A}$ , we can conclude that $\overrightarrow{\mathbf{B}}$ and $\overrightarrow{\mathbf{C}}$ :

If $\alpha$ = 40 $\degree$ and the tension in string 2 is 30 N, determine M. $If \alpha = 40 \degree and the tension in string 2 is 30 N, determine M.$

Given the equation $(2.00 \mathrm{~kg})\left(5.00 \frac{\mathrm{~m}}{\mathrm{~s}^{2}}\right)=20.00 \mathrm{~N}-10.00 \mathrm{~N}$ , which answer or answers provide(s) the best description of a possible physical situation?

A 2000-kg sailboat heading out to sea through the Sydney heads experiences an eastward force of 3000 N by the ocean tide and a wind force against its sails of magnitude 6000 N directed toward the northwest (45 $\degree$ N of W). What is the magnitude and direction of the resultant acceleration?