The second option rolling friction
<h2>Right answer: a number and a unit</h2>
The measurement consists in <em>comparing a selected pattern with the object or phenomenon whose physical magnitude is going to be measured, to find out how many times the pattern is contained in that magnitude.</em> That is, it is about identifying or quantifying a particular characteristic or aspect of a particular object or construct.
Now, a well done measurement has two parts:
-The number gives us information about the quantity of the measurement, or in other words, the magnitude of the measurement and its precision.
-The units gives us information about the property that is being measured. This is quite important, because a measurement or result with no units is useless.
Note the units may be expressed with letter or symbols, depending on what we are measuring.
Answer is B
Hope this helped!
Answer:
-1.03 m/s²
Explanation:
Acceleration: This can be defined as the rate of change of velocity. The S. I unit of acceleration is m/s².
Mathematically, acceleration is expressed as
a = (v-u)/t ........................ Equation 1
Where a = acceleration, v = final velocity, u = initial velocity, t = time.
Given: u = 13.60 m/s, v = 7.20 m/s t = 6.2 s.
Substituting into equation 2
a = (7.20-13.60)/6.2
a = -6.4/6.2
a = -1.03 m/s²
Note: a is negative because, the hockey puck is decelerating.
Hence the average acceleration = -1.03 m/s²
Answer:
a)W= - 47.19 J
b)47.19 J
Explanation:
Given that
Weight ,mg= 71.5 N
y= 1.84 m
H= 2.5
a)
The distance above the hand ,h= 2.5 - 1.84 m
h= 0.66 m
We know that gravitaional force act in the downward direction but the displacement is in upward direction that is why work done will be negative.
W= - m g h
W= -71.5 x 0.66 J
W= - 47.19 J
b)
The potential energy at initial position = m g y
The potential energy at final position = m g H
So change in the potential energy = m g H - m g y
= mg ( H- y)
=71.5 ( 2.5 - 1.84 ) = 47.19 J
Therefore change in the potential energy = 47.19 J
