Question 1

An elevator,with a total mass of 454 kg,accelerates downward at 3.51 m/s².During this time,the tension in the elevator cable is

Accepted Answer

C

Question 2

Two objects are not in contact,but they affect each other via gravity,and there are no other forces acting on either object.Which statement is always true?

Accepted Answer

According to Newton's law of universal gravitation, the force of gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of their distance apart. Therefore, the magnitude of the force of gravity is the same on both objects regardless of their masses, and the distance between them.

Question 3

A skydiver of mass 90.0 kg (including outfit and equipment)floats down suspended from his parachute,having reached terminal speed,8.35 m/s.The area of his parachute is 40.0 m² and the density of air is 1.15 kg/m³.The drag coefficient is

Accepted Answer

D

Question 4

A 100-kg object rests on a level surface with a coefficient of friction (both static and kinetic)of 0.40.If a 250 N force is applied,find the magnitude of the acceleration of the object.

Accepted Answer

The answer of A 100-kg object rests on a level...

Question 5

Two blocks,B1 and B2 with masses of 12.0 kg and 5.60 kg,respectively,are in contact with each other on a frictionless horizontal surface.A purely horizontal force of 30.0 N is applied to B1,which in turn pushes B2 and both blocks accelerate together uniformly.The net horizontal force acting on B2 is

Accepted Answer

The net force acting on the system is 30.0 N, and it accelerates both blocks together. The acceleration of the system can be found using Newton's second law, $F = ma$, where $F$ is the total force applied, $m$ is the total mass, and $a$ is the acceleration. The total mass is $12.0 \, \text{kg} + 5.60 \, \text{kg} = 17.6 \, \text{kg}$. Thus, the acceleration $a$ of the system is $30.0 \, \text{N} / 17.6 \, \text{kg} = 1.7045 \, \text{m/s}^2$.The net force on B2 can be found by multiplying its mass by the acceleration of the system: $F = m \cdot a = 5.60 \, \text{kg} \cdot 1.7045 \, \text{m/s}^2 = 9.5452 \, \text{N}$, which rounds to $9.55 \, \text{N}$.

Question 6

The two blocks in the figure have masses M₁ and M₂ such that M₁ < M₂ and they lay on a level,frictionless surface.We can apply a horizontal force F either from the left or from the right,as depicted in the figure.The contact force between masses M₁ and M₂ is

Accepted Answer

The answer of The two blocks in the figure have...

Question 7

A 100-kg object moves on a level surface with a coefficient of friction of 0.40.If the initial velocity is 15 m/s,how long will it take for it to come to rest?

Accepted Answer

To find the time it takes for the object to come to rest, we first calculate the force of friction acting on it, which is given by $F_{friction} = \mu \times m \times g$, where $\mu$ is the coefficient of friction, $m$ is the mass of the object, and $g$ is the acceleration due to gravity (approximately $9.8 \, m/s^2$). For a 100-kg object with a coefficient of friction of 0.40, the force of friction is $F_{friction} = 0.40 \times 100 \, kg \times 9.8 \, m/s^2 = 392 \, N$.This frictional force acts as the decelerating force, so we can use Newton's second law to find the deceleration $a = F/m$, which gives us $a = 392 \, N / 100 \, kg = 3.92 \, m/s^2$.To find the time it takes for the object to come to rest, we use the equation $v = u + at$, where $v$ is the final velocity (0 m/s for coming to rest), $u$ is the initial velocity (15 m/s), and $a$ is the deceleration (-3.92 m/s^2, negative because it's deceleration). Rearranging for $t$, we get $t = (v - u) / a = (0 - 15) / -3.92 = 3.83 \, s$, which rounds to approximately 3.8 seconds.

Question 8

In order to straighten a crooked tree,a rope is attached horizontally from the top of the tree to a nearby building.A force of 600 N is applied downward at the center of rope.The angle between this downward force and the rope going to the tree is 95 degrees,which is the same as the angle between the downward force and the rope going to the building.The tension in the rope going to the tree is

Accepted Answer

Let T be the tension in the rope going to the tree, and let F be the force applied at the center of the rope. Then we can resolve forces horizontally and vertically:

Horizontal forces: T cos(95) = F = 600 N
Vertical forces: T sin(95) = W

where W is the weight of the tree. Since the problem only asks for the tension in the rope, we can ignore W. Solving for T:

T = F / cos(95) = 600 N / cos(95) = 3442 N (rounded to the nearest whole number)

Question 9

A climber pulls on a rope that goes through a single pulley directly above him and then comes back down to an attachment point on his belt.The climber has a mass of 65 kg.The force with which the climber must pull on the rope in order to support himself on the rope is

Accepted Answer

The answer of A climber pulls on a rope that...

Question 10

There are only two forces on an object that has a mass of 10.0 kg.Both forces have a magnitude of 10.0 N.The angle between the forces is 60.0 degrees.What is the magnitude of the object's acceleration?

Accepted Answer

First, we need to find the net force acting on the object. Using vector addition, we can find that the net force has a magnitude of 10 N and makes an angle of 30 degrees with one of the original forces.

Next, we can use Newton's second law (F = ma) to find the acceleration of the object.

F = ma

10 N = (10.0 kg) a

a = 1.00 m/s^2

However, this is the acceleration in the direction of the net force. We are asked for the magnitude of the acceleration, which we can find using trigonometry:

a_mag = a cos(30)

a_mag = (1.00 m/s^2) cos(30)

a_mag = 0.866 m/s^2

This is approximately equal to 1.73 m/s^2, so the best choice is B.

Question 11

Two masses,m₁= 3.0 kg and m₂ = 4.0 kg rest on a frictionless surface as shown.A force of 7.0 N is applied to m₁.What is the acceleration of the two masses?

Accepted Answer

The answer of Two masses,m₁= 3.0 kg and m₂ =...

Question 12

A skydiver of mass 90.0 kg (including outfit and equipment)floats down suspended from his parachute,having reached terminal speed of 12.3 m/s.The drag coefficient is 0.533,and the density of air is 1.15 kg/m³.The area of her parachute is

Accepted Answer

The answer of A skydiver of mass 90.0 kg (including...

Question 13

An 85.0-kg snowboarder slides down a frictionless slope inclined at an angle of 30S1U1P1$\circ$S1S1P0.What is her acceleration?

Accepted Answer

The acceleration of the snowboarder can be found using the formula $a = g \sin(\theta)$, where $g = 9.81 \, m/s^2$ is the acceleration due to gravity and $\theta = 30^\circ$. Substituting the given values, $a = 9.81 \sin(30^\circ) = 9.81 \times 0.5 = 4.905 \, m/s^2$, which rounds to $4.91 \, m/s^2$.

Question 14

A force of 100.0 N is applied to an object of mass 85.0 kg.What is the object's acceleration?

Accepted Answer

The acceleration can be calculated using Newton's second law of motion, $F = ma$, where $F$ is the force applied, $m$ is the mass of the object, and $a$ is the acceleration. Rearranging for $a$, we get $a = \frac{F}{m}$. Substituting the given values, $a = \frac{100.0\, \text{N}}{85.0\, \text{kg}} = 1.176\, \text{m/s}^2$, which rounds to 1.18 m/s$^2$, matching choice A.

Question 15

A package rests on the back seat of your car.The coefficient of friction between the seat and the package is 0.24.Assuming you drive on a level road,what is the maximum acceleration your car can have if the package is to remain in place relative to your back seat?

Accepted Answer

The maximum acceleration without the package sliding is equal to the coefficient of static friction times the acceleration due to gravity (g = 9.8 m/s^2). Thus, maximum acceleration = 0.24 * 9.8 m/s^2 = 2.352 m/s^2, which is closest to 2.4 m/s^2.

Question 16

The mass of an object is

Accepted Answer

Mass is a measure of the amount of matter in an object and remains constant regardless of location, while weight is the force exerted by gravity on that mass and varies with the strength of the gravitational field.

Question 17

What determines the magnitude of the force of static friction on an object at rest at all times on a flat level horizontal surface being pushed to the right by another solid object?

Accepted Answer

The answer of What determines the magnitude of the force...

Question 18

The direction of the normal force is always

Accepted Answer

The normal force is defined as the force perpendicular to the surface of contact between two objects. Therefore, the correct answer is choice B, perpendicular to the surface of contact.

Question 19

Four weights,of masses m₁ = 3.00 kg,m₂ = 1.00 kg,m₃ = 4.00 kg,m₄ = 2.00 kg,are hanging from the ceiling as shown.They are connected to each other with ropes.The tension in the rope connecting the masses m₁ and m₂ is

Accepted Answer

The answer of Four weights,of masses m₁ = 3.00 kg,m₂...

Question 20

A force is applied to a 100-kg go-cart to accelerate it from 10.0 m/s to 20.0 m/s over a 7.00 s time frame.If the acceleration is assumed to be constant over the time frame,what is the magnitude of the force applied?

Accepted Answer

First, calculate the acceleration using the formula $a = \frac{\Delta v}{\Delta t}$, where $\Delta v = 20.0 \, \text{m/s} - 10.0 \, \text{m/s} = 10.0 \, \text{m/s}$ and $\Delta t = 7.00 \, \text{s}$. This gives $a = \frac{10.0 \, \text{m/s}}{7.00 \, \text{s}} = 1.43 \, \text{m/s}^2$. Then, use Newton's second law, $F = ma$, with $m = 100 \, \text{kg}$ and $a = 1.43 \, \text{m/s}^2$, to find $F = 100 \, \text{kg} \times 1.43 \, \text{m/s}^2 = 143 \, \text{N}$.

Quiz 4: Force

An elevator,with a total mass of 454 kg,accelerates downward at 3.51 m/s².During this time,the tension in the elevator cable is

Two objects are not in contact,but they affect each other via gravity,and there are no other forces acting on either object.Which statement is always true?

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed,8.35 m/s.The area of his parachute is 40.0 m² and the density of air is 1.15 kg/m³.The drag coefficient is

A 100-kg object rests on a level surface with a coefficient of friction (both static and kinetic) of 0.40.If a 250 N force is applied,find the magnitude of the acceleration of the object.

Two blocks,B1 and B2 with masses of 12.0 kg and 5.60 kg,respectively,are in contact with each other on a frictionless horizontal surface.A purely horizontal force of 30.0 N is applied to B1,which in turn pushes B2 and both blocks accelerate together uniformly.The net horizontal force acting on B2 is

The two blocks in the figure have masses M₁ and M₂ such that M₁ < M₂ and they lay on a level,frictionless surface.We can apply a horizontal force F either from the left or from the right,as depicted in the figure.The contact force between masses M₁ and M₂ is

A 100-kg object moves on a level surface with a coefficient of friction of 0.40.If the initial velocity is 15 m/s,how long will it take for it to come to rest?

A climber pulls on a rope that goes through a single pulley directly above him and then comes back down to an attachment point on his belt.The climber has a mass of 65 kg.The force with which the climber must pull on the rope in order to support himself on the rope is

There are only two forces on an object that has a mass of 10.0 kg.Both forces have a magnitude of 10.0 N.The angle between the forces is 60.0 degrees.What is the magnitude of the object's acceleration?

Two masses,m₁= 3.0 kg and m₂ = 4.0 kg rest on a frictionless surface as shown.A force of 7.0 N is applied to m₁.What is the acceleration of the two masses?

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed of 12.3 m/s.The drag coefficient is 0.533,and the density of air is 1.15 kg/m³.The area of her parachute is

An 85.0-kg snowboarder slides down a frictionless slope inclined at an angle of 30^$\circ$.What is her acceleration?

A force of 100.0 N is applied to an object of mass 85.0 kg.What is the object's acceleration?

A package rests on the back seat of your car.The coefficient of friction between the seat and the package is 0.24.Assuming you drive on a level road,what is the maximum acceleration your car can have if the package is to remain in place relative to your back seat?

The mass of an object is

What determines the magnitude of the force of static friction on an object at rest at all times on a flat level horizontal surface being pushed to the right by another solid object?

The direction of the normal force is always

Four weights,of masses m₁ = 3.00 kg,m₂ = 1.00 kg,m₃ = 4.00 kg,m₄ = 2.00 kg,are hanging from the ceiling as shown.They are connected to each other with ropes.The tension in the rope connecting the masses m₁ and m₂ is

A force is applied to a 100-kg go-cart to accelerate it from 10.0 m/s to 20.0 m/s over a 7.00 s time frame.If the acceleration is assumed to be constant over the time frame,what is the magnitude of the force applied?

Quiz 4: Force

An elevator,with a total mass of 454 kg,accelerates downward at 3.51 m/s2.During this time,the tension in the elevator cable is

Two objects are not in contact,but they affect each other via gravity,and there are no other forces acting on either object.Which statement is always true?

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed,8.35 m/s.The area of his parachute is 40.0 m2 and the density of air is 1.15 kg/m3.The drag coefficient is

A 100-kg object rests on a level surface with a coefficient of friction (both static and kinetic) of 0.40.If a 250 N force is applied,find the magnitude of the acceleration of the object.

The two blocks in the figure have masses M1 and M2 such that M1 < M2 and they lay on a level,frictionless surface.We can apply a horizontal force F either from the left or from the right,as depicted in the figure.The contact force between masses M1 and M2 is

A 100-kg object moves on a level surface with a coefficient of friction of 0.40.If the initial velocity is 15 m/s,how long will it take for it to come to rest?

A climber pulls on a rope that goes through a single pulley directly above him and then comes back down to an attachment point on his belt.The climber has a mass of 65 kg.The force with which the climber must pull on the rope in order to support himself on the rope is

There are only two forces on an object that has a mass of 10.0 kg.Both forces have a magnitude of 10.0 N.The angle between the forces is 60.0 degrees.What is the magnitude of the object's acceleration?

Two masses,m1= 3.0 kg and m2 = 4.0 kg rest on a frictionless surface as shown.A force of 7.0 N is applied to m1.What is the acceleration of the two masses?

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed of 12.3 m/s.The drag coefficient is 0.533,and the density of air is 1.15 kg/m3.The area of her parachute is

An 85.0-kg snowboarder slides down a frictionless slope inclined at an angle of 30 ∘\circ∘ .What is her acceleration?

A force of 100.0 N is applied to an object of mass 85.0 kg.What is the object's acceleration?

A package rests on the back seat of your car.The coefficient of friction between the seat and the package is 0.24.Assuming you drive on a level road,what is the maximum acceleration your car can have if the package is to remain in place relative to your back seat?

The mass of an object is

What determines the magnitude of the force of static friction on an object at rest at all times on a flat level horizontal surface being pushed to the right by another solid object?

The direction of the normal force is always

Four weights,of masses m1 = 3.00 kg,m2 = 1.00 kg,m3 = 4.00 kg,m4 = 2.00 kg,are hanging from the ceiling as shown.They are connected to each other with ropes.The tension in the rope connecting the masses m1 and m2 is

A force is applied to a 100-kg go-cart to accelerate it from 10.0 m/s to 20.0 m/s over a 7.00 s time frame.If the acceleration is assumed to be constant over the time frame,what is the magnitude of the force applied?

An elevator,with a total mass of 454 kg,accelerates downward at 3.51 m/s².During this time,the tension in the elevator cable is

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed,8.35 m/s.The area of his parachute is 40.0 m² and the density of air is 1.15 kg/m³.The drag coefficient is

The two blocks in the figure have masses M₁ and M₂ such that M₁ < M₂ and they lay on a level,frictionless surface.We can apply a horizontal force F either from the left or from the right,as depicted in the figure.The contact force between masses M₁ and M₂ is

Two masses,m₁= 3.0 kg and m₂ = 4.0 kg rest on a frictionless surface as shown.A force of 7.0 N is applied to m₁.What is the acceleration of the two masses?

A skydiver of mass 90.0 kg (including outfit and equipment) floats down suspended from his parachute,having reached terminal speed of 12.3 m/s.The drag coefficient is 0.533,and the density of air is 1.15 kg/m³.The area of her parachute is

An 85.0-kg snowboarder slides down a frictionless slope inclined at an angle of 30^$\circ$.What is her acceleration?

Four weights,of masses m₁ = 3.00 kg,m₂ = 1.00 kg,m₃ = 4.00 kg,m₄ = 2.00 kg,are hanging from the ceiling as shown.They are connected to each other with ropes.The tension in the rope connecting the masses m₁ and m₂ is