a. 4.52 m/s south
Velocity is a vector, whose magnitude is defined as the ratio between the displacement of the object and the time taken for the displacement to occur:
where
d is the displacement
t is the time
Velocity is a vector, so it also has a direction, which corresponds to that of the displacement.
For the ball in this problem,
d = 9.5 m south
t = 2.1 s
Substituting, we find:
and the directiion is the same as the displacement (south).
b. 4.52 m/s north
For this part, we must keep in mind that the speed is the magnitude of the velocity; however, speed is a scalar, so it does not have a direction.
Here we are told that the tennis ball travels at constant speed, so on its way back from Liam to Katie the ball's velocity is still the same as before, therefore
However, this time the direction is opposite to before, since the ball is travelling in the opposite direction.
Therefore, the ball's velocity when Liam returns Katie's service is
4.52 m/s north
Answering the question, three examples of ways that physicists model the physical world include:
- Diagrams
- Equations
- Computer simulations
Computer simulations refer to the reproduction of behavior of a system with the use of a computer to simulate the results of a mathematical model that is linked with the system.
<h2>Further Explanation</h2>
Computer simulations are a tool that is very useful for mathematical modeling in various natural systems in physics.
Physicists write the rule of our universe using equations. Equations are an aspect of one of the models used by physicists to explain a particular situation.
Physicists use a diagram to convey information. It is a symbolic representation of information with the use of visualization techniques. Diagram provides other means for people to better understand information and process its importance.
Physics predictions about the physical world mainly depend on numerical stimulation, mathematics and empirical observations and Physicists models the physical world based on invariances and laws which are built on mathematical models.
The purpose of physics is to explain or describe everything around us. It described virtually everything around us accurately by deploring the law of physics.
However, physics is considered a natural science because it is based on mathematical analysis which is geared towards findings qualitative physical law for the physical world.
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KEYWORDS:
- physicists
- physics
- models
- physical world
- computer simulations
- diagrams
- equations
This question is wrong because of not correct values.The Correct question is
A gas in a cylinder is held at a constant pressure of 1.80×10⁵Pa and is cooled and compressed from 1.70m³ to 1.20m³. The internal energy of the gas decreases by 1.40×10⁵J.
(a) Find the work done by the gas.
(b) Find the absolute value of the heat flow, |Q|, into or out of the gas, and state the direction of the heat flow.
(c) Does it matter whether the gas is ideal? Why or why not?
Answer:
(a) W= -9×10⁴J
(b) |Q|=2.3×10⁵
(c) It does not matter whether gas is ideal or non-ideal
Explanation:
Given
V₁=1.70m³
V₂=1.20m³
p=1.8×10⁵ pa
ΔU= -1.40×10⁵J
For (a) work done by gas
For (b) Heat flow |Q|
|Q|=ΔU+W
For (c) part
It does not matter whether the gas is ideal or not because the first law of thermodynamics which applied in our solution could applied to any material ideal or non ideal
Positive terminal with Positive terminal. The negative terminal should be connected to the car chassis.
Answer: 9.312 m/s
Explanation:
The friction force (opposite to the motion) is Fa = μ*m*g*cos(α) with μ = kinetic friction. The force that makes the motion is
F = m*g*sin(α).
The Newton's law gives:
F - Fa = m*a
m*g*sin(α) - μ*m*g*cos(α) = m*a
g*sin(α) - μ*g*cos(α) = a so a = 4.335 m/s²
It's a uniformly accelerated motion:
Space
S = 0.5*a*t²
10 = 0.5*a*t²
=> t = 2.148 s
Velocity
V = a*t = 9.312 m/s.