The work done occurs only in the direction the block was moved - horizontally. Work is given by:
W = F(h) * d
Where F(h) is the force applied in that direction (horizontal) and d is the distance in that direction. In this case, F(h) is the horizontal component of the applied force, F(app). However, the question doesn't give us F(app), so we need to find it some other way.
Since the block is moving at a constant speed, we know the horizontal forces must be balanced so that the net force is 0. This means that F(h) must be exactly balanced by the friction force, f. We can express F(h) as a function of F(app):
F(h) = F(app)cos(23)
Friction is a little trickier - since the block is being PUSHED into the ground a bit by the vertical component of the applied force, F(v), the normal force, N, is actually a bit more than mg:
N = mg + F(v) = mg + F(app)sin(23)
Now we can get down to business and solve for F(app) - as mentioned above:
F(h) = f
F(h) = uN
F(h) = u * (mg + F(v))
F(app)cos(23) = 0.20 * (33 * 9.8 + F(app)sin(23))
F(app) = 76.8
Now that we have F(app), we can find the exact value of F(h):
F(h) = F(app)cos(23)
F(h) = 76.8cos(23)
F(h) = 70.7
And now that we have F(h), we can find W:
W = F(h) * d
W = 70.7 * 6.1
W = 431.3
Therefore, the work done by the worker's force is 431.3 J. This also represents the increase in thermal energy of the block-floor system.
The statement that is a quantitative observation is that bird has four different colors on it (option B).
<h3>What is a quantitative research?</h3>
A quantitative research is a systematic scientific investigation of quantitative properties and phenomena and their relationships, using statistical methods.
A quantitative observation has to do with numbers or numeric analysis.
This suggests that the statement that is a quantitative observation is that bird has four different colors on it.
Learn more about quantitative observations at: brainly.com/question/1434538
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<h2>Answer:</h2>
<h2>Explanation:</h2>
First, let's refer to the distance formula:
, where d is distance, v is velocity or speed and t is time.
Now, let's find the distance covered by each individual speed that the car had:
<h3>1. Speed 1.</h3>
In order to use the formula, we need to convert minutes into hours since the speed is given in km/h.
21.1 min/60= 0.35 h.
Now, apply the distance formula.
d=(0.35h)*(86.8km/h)= 30.38 km.
<h3>2. Speed 2.</h3>
Convert minutes to hours again and do the same calculations.
10.6min/60=0.18h
d=(0.18h)*(106km/h)= 19.08 km.
<h3>3. Speed 3.</h3>
36.5min/60= 0.61h
d=(0.61h)*(30.9km/h)= 18.85 km.
<h3>4. Obtain the total distance.</h3>
The total distance must be given by the addition of all individual distances traveled by the car on each speed:
Total distance= 30.38 km + 19.08 km + 18.85 km= 68.31 km.
