Answer: representative sample
Explanation:
A representative sample can be defined as a subset of the population. This sample includes subgroups that reflect the features of the larger group and are chosen for a specific purpose of study. For example, a classroom with 60 students having 30 females and 30 males, can generate a representative sample based on the gender differences.
Answer:
option the correct is B
Explanation:
Let's analyze the different options, for a closed system
- an internal reaction changes the system, but does not affect the surrounding environment
- Heat, is a means of transfer that occurs when two bodies are in contact, one of the body can be a closed system since the only thing that happens is thermal transfer, without movement of the system itself. This is the correct result.
- Work implies a movement whereby the system must be mobile, it is not an option
- Pressure change. change in the system, but does not affect the environment
- Mass transfer is not possible in a closed system
After analyzing each option the correct one in B
The car, accelerating at a constant rate of 2.0 m/s2 from rest, will travel a distance of 144 meters in 12 seconds.
The question pertains to the concept of motion in physics, specifically how distances travelled are influenced by an object's acceleration. The car is accelerating at a constant rate of 2.0 m/s2 from rest. It means that the initial velocity of the car is 0. We can use the formula of motion, s = ut + 0.5at2, where u is the initial velocity, a is the acceleration and t is the time.
In this case, u = 0 (as the car starts from rest), a = 2.0 m/s2 (constant acceleration) and t = 12 seconds. Substituting these values into the formula, we get:
s = 0*12 + 0.5*2*122
Therefore, the car will travel 144 meters in 12 seconds assuming it accelerates at a constant rate.
#SPJ2
Answer:149.73 ml
Explanation:
Given
change in volume is given by
The volume of the acetone when it cools to 20.0°C is approximately 142.39 mL.
In order to determine the volume of the acetone when it cools to 20.0°C, we can use the equation for the volume change caused by a temperature change at constant pressure, known as Charles's law. Charles's law states that the volume of a gas is directly proportional to its temperature in Kelvin. We can use the formula V2 = V1 * (T2 / T1) to calculate the volume of the acetone at the lower temperature.
Given that the initial volume of the acetone is 150 mL at a temperature of 34.5°C, we need to convert this temperature to Kelvin by adding 273.15. Therefore, T1 = 34.5°C + 273.15 = 307.65 K.
Since the final temperature is 20.0°C, the final temperature in Kelvin will be T2 = 20.0°C + 273.15 = 293.15 K. We can now plug these values into the equation to find the volume of the acetone at the lower temperature: V2 = 150 mL * (293.15 K / 307.65 K) = 142.39 mL.
#SPJ3
Answer:
The time for the change in the angular velocity to occur is 14.08 secs
Explanation:
From the question,
the angular acceleration is - 4.46 rad/s²
Angular acceleration is given by the formula below
Where is the angular acceleration
is the final angular velocity
is the initial angular velocity
is the final time
is the initial time
From the question
= - 4.46 rad/s²
= 0 rad/s (starting from rest)
= -31.4 rad/s
= 0 s
Now, we will determine t
From , then
t = 7.04 secs
This is the time spent in one direction,
Since the angular displacement of the wheel is zero ( it returned to its initial position), then the time required for the change in the angular velocity will be twice this time, that is 2t
Hence,
The time is 2×7.04 secs = 14.08 secs
This is the time for the change in the angular velocity to occur.
The torque about a given origin when a force N is acting on a particle at the position vector m is given by the cross product of the position and force vectors. It's represented by the SI unit Newton-meters, and for multiple particles, the total angular momentum is the vector sum of their individual angular momenta.
The torque about a given origin, when a force N is acting on a particle located at the position vector m, is calculated using the cross product of the position vector and the force vector. This can be written as τ = m x N. The SI unit of torque is Newton-meters (N.m).
As an example, if you apply a force perpendicularly at a distance from a pivot point, you will create a torque relative to that point. Similarly, the torque on a particle is also equal to the moment of inertia about the rotation axis times the angular acceleration.
If we consider multiple particles, the total angular momentum of these particles about the origin is the vector sum of their individual angular momenta. This is calculated by the expression for the angular momentum Ỉ = ŕ x p for each particle, where ŕ is the vector from the origin to the particle and p is the particle's linear momentum.
#SPJ12
The torque on a particle at a position vector m with force N acting on it is calculated by taking the cross-product of the position vector and the force. This principle is the same even in systems with multiple particles. The SI unit of torque is Newton-meters (N·m), which should not be confused with Joules (J).
The torque on a particle located at a position vector m with a force N acting on it is calculated by taking the cross-product of the position vector and the force. In terms of physics, torque (τ) is a measure of the force that can cause an object to rotate about an axis, and it is calculated as the product of the force and the distance from the axis of rotation to the point where force is applied. Hence, the formula for torque is τ = r x F where r is the position vector (or distance from the origin to the point where the force is applied) and F is the force. Remember, this equation gives a vector result with a direction perpendicular to the plane formed by r and F and a magnitude equal to the product of the magnitudes of r and F and the sine of the angle between r and F.
The same principle applies to systems where multiple particles are present. The total angular momentum of the system of particles about a particular point is the vector sum of the individual angular momenta about that point. Torque is the time derivative of angular momentum.
The SI unit for torque is Newton-meters (N·m), which should not be confused with Joules (J), as both have the same base units but represent different physical concepts. In this context, a net force of 40N acting at a distance of 0.800m from the origin would generate a torque of 32 N·m at the origin.
#SPJ11