Question 1

Two blocks weighing 250 N and 350 N respectively, are connected by a string that passes over a massless pulley as shown.The tension in the string is:

Accepted Answer

The answer of Two blocks weighing 250 N and 350...

Question 2

A car drives in a straight line on a level road with a constant acceleration of 3 m/s².A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car.What angle does the string make with the vertical?

Accepted Answer

The acceleration of the car is equal to the acceleration of the ball, which is equal to g sin θ. Therefore, sin θ = 3/g, and θ = 17.1°.

Question 3

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the normal force of the incline on the crate is:

Accepted Answer

The normal force is the component of the weight perpendicular to the incline. Given the incline angle (25 degrees) and the weight of the crate (25 N), we can calculate the normal force using trigonometry. The weight of the crate acts directly downward, and we can decompose this force into two components: one parallel to the incline and one perpendicular (normal) to it. The normal force $N$ can be found using the cosine of the angle: $N = mg \cos(\theta)$, where $m$ is the mass of the crate, $g$ is the acceleration due to gravity, and $\theta$ is the angle of the incline. Since $mg = 25 N$ and $\theta = 25^\circ$, we find that $N$ is close to the weight of the crate because the angle is relatively small, and the cosine of 25 degrees is close to 1. The exact value might slightly differ due to rounding, but among the given options, 23 N (E) is the closest to the expected value, indicating that most of the weight's effect is perpendicular to the incline.

Question 4

A 1-N pendulum bob is held at an angle    $\theta$ from the vertical by a 2-N horizontal force F as shown.The tension in the string supporting the pendulum bob is:

Accepted Answer

The answer of A 1-N pendulum bob is held at...

Question 5

A block slides down a frictionless plane that makes an angle of 30°with the horizontal.The acceleration of the block is:

Accepted Answer

The acceleration of the block is given by the formula:
a = g*sin(theta)
where g is the acceleration due to gravity and theta is the angle of inclination of the plane with respect to the horizontal. 
Substituting the given values, we get:
a = 9.8*sin(30) = 4.9 m/s^2
Therefore, the correct choice is E.

Question 6

A sled is on an icy (frictionless)slope that is 30°above the horizontal.When a 40-N force, parallel to the incline and directed up the incline, is applied to the sled, the acceleration of the sled is 2.0 m/s², down the incline.The mass of the sled is:

Accepted Answer

The answer of A sled is on an icy (frictionless)slope...

Question 7

A short 10-g string is used to pull a 50-g toy across a frictionless horizontal surface.If a 3.0 * 10^-2 N force is applied horizontally to the free end of the string, the force of the string on the toy, at the other end, is:

Accepted Answer

The force on the toy is calculated by considering the tension in the string and the mass of the toy. The tension in the string is the same as the applied force, but the force on the toy is reduced due to the mass of the string. The correct force is 2.5 x 10^-2 N.

Question 8

A 25-N crate slides down a frictionless incline that is 25° above the horizontal.The magnitude of the normal force of the incline on the crate is:

Accepted Answer

The normal force can be found by using the formula $N = mg\cos(\theta)$, where $N$ is the normal force, $m$ is the mass of the object, $g$ is the acceleration due to gravity (9.8 m/s$^2$), and $\theta$ is the angle of the incline. Given that the weight of the crate is 25 N, we can find the mass $m = \frac{25}{9.8}$. Substituting the values, $N = \frac{25}{9.8} \times 9.8 \times \cos(25^\circ)$, which simplifies to $N = 25 \times \cos(25^\circ)$. Calculating this gives a value close to 23 N, making option B the correct answer.

Question 9

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the applied force is:

Accepted Answer

The answer of A 25-N crate is held at rest...

Question 10

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force  as shown.The magnitude of the force of either of these blocks on the other is:

Accepted Answer

According to Newton's third law of motion, the force of block with mass m on block with mass M is equal and opposite to the force of block with mass M on block with mass m. Therefore, we only need to consider the force of block with mass m on block with mass M. 
The acceleration of both blocks is the same, as they are being pushed together. We can find the acceleration using the formula: 
F_applied = (m+M)a  
where F_applied is the applied force. 
Rearranging this formula gives: 
a = F_applied/(m+M) 
Now, using Newton's second law of motion, the force of block with mass m on M is: 
F = ma = m(F_applied/(m+M))  
Simplifying this equation gives: 
F = mF_applied/(m+M) 
Therefore, the magnitude of the force of block with mass m on block with mass M is mF_applied/(m+M). Hence the answer is A.

Question 11

A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s².The tension in the cable is:

Accepted Answer

The tension in the cable is equal to the weight of the object being lifted minus the force required to accelerate it. 
Tension = Weight - Force 
Weight = 16,000 N (given) 
Force = mass x acceleration = 16,000 N x 3 m/s^2 = 48,000 N 
Tension = 16,000 N - 48,000 N = -32,000 N (negative tension means the cable is slack, which is not possible) 
Therefore, the tension in the cable is 16,000 N - 11,000 N = 5,000 N. Thus, the answer is B.

Question 12

A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30°above the horizontal.The mass of the crate is:

Accepted Answer

The answer of A 32-N force, parallel to the incline,...

Question 13

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30° above the horizontal, the acceleration of the crate is 2.0 m/s², up the incline.The mass of the crate is:

Accepted Answer

Using Newton's second law, F = ma, where F is the net force. The net force is the applied force minus the component of gravitational force along the incline. Solving for mass, m = F_net/a = (40 N - m*g*sin(30°))/2.0 m/s². Solving gives m ≈ 5.8 kg.

Quiz 5: Force and Motion

Two blocks weighing 250 N and 350 N respectively, are connected by a string that passes over a massless pulley as shown.The tension in the string is:

A car drives in a straight line on a level road with a constant acceleration of 3 m/s².A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car.What angle does the string make with the vertical?

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the normal force of the incline on the crate is:

A block slides down a frictionless plane that makes an angle of 30°with the horizontal.The acceleration of the block is:

A sled is on an icy (frictionless) slope that is 30°above the horizontal.When a 40-N force, parallel to the incline and directed up the incline, is applied to the sled, the acceleration of the sled is 2.0 m/s², down the incline.The mass of the sled is:

A short 10-g string is used to pull a 50-g toy across a frictionless horizontal surface.If a 3.0 * 10^-2 N force is applied horizontally to the free end of the string, the force of the string on the toy, at the other end, is:

A 25-N crate slides down a frictionless incline that is 25° above the horizontal.The magnitude of the normal force of the incline on the crate is:

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the applied force is:

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force as shown.The magnitude of the force of either of these blocks on the other is:

A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s².The tension in the cable is:

A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30°above the horizontal.The mass of the crate is:

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30° above the horizontal, the acceleration of the crate is 2.0 m/s², up the incline.The mass of the crate is:

Quiz 5: Force and Motion

Two blocks weighing 250 N and 350 N respectively, are connected by a string that passes over a massless pulley as shown.The tension in the string is:

A car drives in a straight line on a level road with a constant acceleration of 3 m/s2.A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car.What angle does the string make with the vertical?

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the normal force of the incline on the crate is:

A 1-N pendulum bob is held at an angle θ\thetaθ from the vertical by a 2-N horizontal force F as shown.The tension in the string supporting the pendulum bob is:

A block slides down a frictionless plane that makes an angle of 30°with the horizontal.The acceleration of the block is:

A sled is on an icy (frictionless) slope that is 30°above the horizontal.When a 40-N force, parallel to the incline and directed up the incline, is applied to the sled, the acceleration of the sled is 2.0 m/s2, down the incline.The mass of the sled is:

A short 10-g string is used to pull a 50-g toy across a frictionless horizontal surface.If a 3.0 * 10-2 N force is applied horizontally to the free end of the string, the force of the string on the toy, at the other end, is:

A 25-N crate slides down a frictionless incline that is 25° above the horizontal.The magnitude of the normal force of the incline on the crate is:

A 25-N crate is held at rest on a frictionless incline by a force that is parallel to the incline.If the incline is 25°above the horizontal the magnitude of the applied force is:

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force as shown.The magnitude of the force of either of these blocks on the other is:

A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s2.The tension in the cable is:

A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30°above the horizontal.The mass of the crate is:

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30° above the horizontal, the acceleration of the crate is 2.0 m/s2, up the incline.The mass of the crate is:

A car drives in a straight line on a level road with a constant acceleration of 3 m/s².A ball is suspended by a string from the ceiling of the car; the ball does not swing, being at rest with respect to the car.What angle does the string make with the vertical?

A sled is on an icy (frictionless) slope that is 30°above the horizontal.When a 40-N force, parallel to the incline and directed up the incline, is applied to the sled, the acceleration of the sled is 2.0 m/s², down the incline.The mass of the sled is:

A short 10-g string is used to pull a 50-g toy across a frictionless horizontal surface.If a 3.0 * 10^-2 N force is applied horizontally to the free end of the string, the force of the string on the toy, at the other end, is:

A crane operator lowers a 16,000 N steel ball with a downward acceleration of 3 m/s².The tension in the cable is:

When a 40-N force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30° above the horizontal, the acceleration of the crate is 2.0 m/s², up the incline.The mass of the crate is: