By definition, vectors are quantities that have magnitude (positive or negative) and direction.
Graphically, they are illustrated by directed line segments, with arrows that indicate the direction.
Evaluate the given statements.
1. Vectors have a size only. FALSE
2. Vectors have a size and a direction. TRUE
3. Vectors are indicated with arrows. TRUE
4. Vectors can have only positive values. FALSE
5. Vectors can have positive or negative values. TRUE
Answer:
I₂ = 0.04 W / m²
Explanation:
Sound intensity is the power emitted between the unit area
I = W / A
W = I A
sound is a wave that travels in space whereby its energy is distributed on the surface of a sphere
A = 4π r²
we substitute
W = I (4π r²)
the emission power is constant, so the intensity at two different points is
W = I₁ 4π r₁² = I₂ 4π r₂²
so the equation is
I₁ r₁² = I₂ r₂²
In this case the units are not shown in the exercise, suppose that all units are in the SI system
I₂ = 
let's calculate
I₂ = 4 
I₂ = 0.04 W / m²
Near the Earth's surface, a freely falling body has constant acceleration at every instant of its fall ... 9.8 meters per second^2.
Answer:
1) True, 2) True, 3) False, 4) False, 5) False
Explanation:
1) True. Dissipative energy cannot be recovered, in general it is a form of heat
2) True. The dissipation can be by radiation, heat
3) False. Mechanical energy is divided into K and U but not in equal parts
4) False. When there are dissipative interactions, part of the mechanical energy is set in the form of heat, so its value decreases
5) False. Mechanical energy is the sum of those two energies
Answer:
a. 6
b. 6 m/s²
c. 300 m to the right
d. 30 secs
Explanation:
slope = rise /run
60-0/10-0
= 6
b. slope = acceleration = 6 m/s²
c. d=ut+1/2at²
t=10 (segment A last for 10 secs)
u - initial velocity = 0
so d = 0(10)+1/2*6*10²
=300 m
