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4 years ago

5

An athlete is working out in the weight room.he steadily holds 50 kilograms above his head for 10 seconds which statement is tru

e about this situation

1 answer:

My name is Ann [436]4 years ago

3 0

The athlete is doing work because he prevents the weight from falling downward

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A homing pigeon starts from rest and accelerates uniformly at +4.00 m/s squared for 10.0 seconds. What is its velocity after the

zavuch27 [327]

' +4 m/s² ' means that the pigeon's speed is 4 m/s greater every second.

Starting from zero speed, after 10 seconds, its speed is

(10 x 4m/s) = 40 m/s.

We can't say anything about its velocity, because we have
no information regarding the direction of its flight.

5 0

4 years ago

An airplane takes off from Dallas Texas to fly to new york city traveling ne for 2,760 km the Same plane returns that day to Dal

Kipish [7]

<h3>Answer</h3>

1104 km/hour

<h3>Explanation</h3>

Distance between Dallas Texas to New York = 2760 km

Time the plane took from Dallas to New York = 2 hours

Time the plane took from New York back to Dallas = 2.5 hours

Formula to use

<h3>distance = speed x time </h3>

Speed the plane took from Dallas to New York

2760 = 2 x speed

speed = 2760 / 2

= 1380 km/hour

Speed the plane took from New York to Dallas (ROUND TRIP)

2760 = 2.5 x speed

speed = 2760 / 2.5

= 1104 km/hour

3 0

3 years ago

Read 2 more answers

Find the period of the leg of a man who is 1.83 m in height with a mass of 67 kg. The moment of inertia of a cylinder rotating a

cupoosta [38]

Answer:

2.2 s

Explanation:

Using the equation for the period of a physical pendulum, T = 2π√(I/mgh) where I = moment of inertia of leg about perpendicular axis at one point = mL²/3 where m = mass of man = 67 kg and L = height of man = 1.83 m, g = acceleration due to gravity = 9.8 m/s² and h = distance of leg from center of gravity of man = L/2 (center of gravity of a cylinder)

So, T = 2π√(I/mgh)

T = 2π√(mL²/3 /mgL/2)

T = 2π√(2L/3g)

substituting the values of the variables into the equation, we have

T = 2π√(2L/3g)

T = 2π√(2 × 1.83 m/(3 × 9.8 m/s² ))

T = 2π√(3.66 m/(29.4 m/s² ))

T = 2π√(0.1245 s² ))

T = 2π(0.353 s)

T = 2.22 s

T ≅ 2.2 s

So, the period of the man's leg is 2.2 s

7 0

3 years ago

A crane raises a crate with a mass of 150 kg to a height of 20 m. Given that

Virty [35]

Answer:

$\boxed {\boxed {\sf 29,400 \ Joules}}$

Explanation:

Gravitational potential energy is the energy an object possesses due to its position. It is the product of mass, height, and acceleration due to gravity.

$E_P= m \times g \times h$

The object has a mass of 150 kilograms and is raised to a height of 20 meters. Since this is on Earth, the acceleration due to gravity is 9.8 meters per square second.

m= 150 kg
g= 9.8 m/s²
h= 20 m

Substitute the values into the formula.

$E_p= 150 \ kg \times 9.8 \ m/s^2 \times 20 \ m$

Multiply the three numbers and their units together.

$E_p=1470 \ kg*m/s^2 \times 20 m$

$E_p=29400 \ kg*m^2/s^2$

Convert the units.

1 kilogram meter square per second squared (1 kg *m²/s²) is equal to 1 Joule (J). Our answer of 29,400 kg*m²/s² is equal to 29,400 Joules.

$E_p= 29,400 \ J$

The crate has <u>29,400 Joules</u> of potential energy.

7 0

3 years ago

A 3.5 kg object moving at 8.1 m/s in the positive direction of an x axis has a one-dimensional elastic collision with an object

Tamiku [17]

Answer:

So the mass of the second object M will be 1.951 kg

Explanation:

We have given mass of the first object $m_1=3.5kg$ and its velocity $v_1=8.1m/sec$

Mass of the second object $m_2=M$ it is at rest so its velocity $v_2=0$

From conservation of momentum we know that

Initial momentum = final momentum

So $m_1v_1+m_2v_2=(m_1+m_2)v$

$3.5\times 8.1+M\times 0=(3.5+M)5.2$

$28.35=18.2+5.2M$

M = 1.951 kg

8 0

3 years ago