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Alchen [17]
2 years ago
13

A 2-kg wood block is pulled by a string across a rough horizontal floor. The string exerts a tension force of 30 N on the block

at an angle of 20º above the horizontal. The block moves at constant speed. If the block is pulled for a distance of 3.0 m, how much work is done by the tension force?
Physics
1 answer:
Luden [163]2 years ago
7 0

Answer:

Work done, W = 84.57 Joules

Explanation:

It is given that,

Mass of the wooden block, m = 2 kg

Tension force acting on the string, F = 30 N

Angle made by the block with the horizontal, \theta=20^{\circ}

Distance covered by the block, d = 3 m

Let W is the work done by the tension force. It can be calculated as :

W=F\ cos\theta\times d

W=30\times cos(20)\times 3

W = 84.57 Joules

So, the work done by the tension force is 84.57 Joules. Hence, this is the required solution.

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While practicing S-turns, a consistently smaller half-circle is made on one side of the road than on the other, and this turn is
erica [24]

Answer:

The answer is "4-5-6 because the bank is growing too quickly in the beginning of its turn".

Explanation:

The S-turns is also known as the reference technique, in which the ground track of the aircraft on both sides of a defined ground-based straight-line distance represents 2 different but equivalent circles.  

Throughout the S-turns, on either side of the road, a progressively smaller half-circle is formed, and this turn does not stop until the road or reference line is crossed during the early part of the turn, the twists increase too quickly.

5 0
1 year ago
A race car makes one lap around a track of radius 50 m in 9.0 s. What is the average velocity? *
Oksi-84 [34.3K]

Given that,

Radius of track, r = 50 m

time , t = 9 s

velocity, v = ?

Distance covered by car in one lap around a track is equal to the circumference of the track.

C = 2 π r = 2 * 3.14 * 50

C = 314.159 m

Distance covered by car, s = 314.159 m

Velocity = distance/ time

V = 314.159 / 9

V = 34.9 m/s

The average velocity of car is 34.9 m/s.

7 0
1 year ago
A student measures the pH of a solution to be 6.8. Which should the student add if she wants to decrease the pH of the solution?
zloy xaker [14]
The neutral pH is 7. Less than 7 indicates an acid and more than 7 indicates a base (up to 14).
<span> NaCl - it's a salt (we can't measure the pH)
H2O - it can be an acid but also a base  (the pH it is almost neutral,meaning close to 7 )
HF - it is a strong acid
</span><span> KOH  - it is a strong base (pH=14)
</span>
                        ↓

He needs to use HF (Hydrogen fluoride) to decrease the pH.


7 0
1 year ago
Read 2 more answers
1. Each year at a college, there is a tradition of having a hoop rolling competition. Alex rolls his 0.350 kg hoop down the cour
grigory [225]

Question 1:

Answer:

The moment of inertia of Alex's rolling hoop is 0.197 kg \cdot cm^2

Explanation:

<u>Given</u>:

Mass of the hoop = 0.350 g

Radius of the hoop = 75.0 cm

<u>To Find:</u>

The moment of inertia of Alex's rolling hoop = ?

<u>Solution</u><u>:</u>

The moment of inertia  = mr^2

where

m is the mass

r is the radius

Converting cm to m, we get

75.0 cm = 0.75 m

Now substituting the values,

=> moment of inertia  = (0.350)(0.75)^2

=> moment of inertia  = (0.350)(0.5625)

=> moment of inertia  = (0.197)

Question 2:

Answer:

The combined angular momentum of the masses is 1.76 kg m^2 s^{-1}

If she pulls her arms in to 0.12 m, her new linear speed  is  18.33 m/s^2

Explanation:

Given:

Mass  = 2.0 kg

Radius = 0.8 m

Velocity =  1.2 m/s

a.The combined angular momentum of the masses:

L = r \cdot m \cdot v_1

Substituting the values,

L = 0.8 \cdot 2.0 \cdot 1.1

L= 1.76 kg m^2 s^{-1}

b. If she pulls her arms in to 0.12 m, what is her new linear speed

0.12 \cdot 0.8 \cdot v_2 = 1.76

0.096 cdot v_2 = 1.76

v_2 = \frac{1.76}{0.096}

v_2 = 18.33 m/s^2

6 0
1 year ago
What is the absolute value of the horizontal force that each athlete exerts against the ground?
alexandr402 [8]
Refer to the diagram shown below.

When an athlete is in motion, he/she exerts a vertical force (the person's weight, W) on the ground. The ground exerts an equal and opposite force, N, the normal reaction on the athlete, so that W = N.

At the same time, the ground exerts a horizontal force, F, o n the athlete so that he/she does not slip.
The magnitude of the horizontal force is
F = μN = μW
where μ = the dynamic coefficient of friction.

Answer:  
The horizontal force is μW,
where
W = the weight of the athlete and,
μ = the dynamic coefficient of friction.

6 0
2 years ago
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