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3 years ago

A 66.5-kg hiker starts at an elevation of 1270 m and climbs to the top of a peak 2660 m high.

Physics

1 answer:

anyanavicka [17]3 years ago

8 0

Answer

given,

mass of the hiker = 66.5 kg

elevation of the hiker,h₁ = 1270 m

elevation of top peak,h₂ = 2660 m

a) Change in potential energy

Δ PE = m g h₂ - m g h₁

Δ PE = m g (h₂ - h₁)

Δ PE = 66.5 x 9.8 x (2660 - 1270)

Δ PE = 905863 J

b) Minimum work require by the hiker will be equal to Δ PE = 905863 J

c) yes, it can be more than this, if friction is present on the surface.

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If Scobie could drive a Jetson's flying car at a constant speed of 160.0 km/hr across oceans and space, approximately how long w

DochEvi [55]

Scobie will take 10 days to drive around Earth's equator.

To calculate the time that takes Scobie to drive around Earth's equator we need to find the distance, which is given by the equation of a circumference:

$d = 2\pi r$

<em>Where:</em>

r: is the Earth's radius = 6371 km

Then, the distance is:

$d = 2\pi r = 2\pi*6371 km = 40030.2 km$

Now, if we divide the above distance by the speed of the car we can find the time:

$t = \frac{d}{v} = \frac{40030.2 km}{160.0 km/h} = 250.2 h*\frac{1 d}{24 h} = 10 d$

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3 years ago

A ball on a cart is moving at a rate of 2 m/s. The cart suddenly stops and the ball continues to travel in the same direction at

sukhopar [10]

Answer:

The first

Explanation:

Cause it will continue in motion till another force is applied

7 0

3 years ago

Read 2 more answers

A disk of radius 10 cm speeds up from rest. it turns 60 radians reaching an angular velocity of 15 rad/s. what was the angular a

stepan [7]

Answer:

a) α = 1.875 $\frac{rad}{s^{2} }$

b) t = 8 s

Explanation:

Given:

ω1 = 0 $\frac{rad}{s}$

ω2 = 15 $\frac{rad}{s}$

theta (angular displacement) = 60 rad

*side note: you can replace regular, linear variables in kinematic equations with angular variables (must entirely replace equations with angular variables)*

a) α = ?

(ω2)^2 = (ω1)^2 + 2α(theta)

$15^{2}$ = $0^{2}$ + 2(α)(60)

225 = 120α

α = 1.875 $\frac{rad}{s^{2} }$

α = (ω2-ω1)/t

t = (ω2-ω1)/α = (15-0)/1.875 = 8

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4 0

3 years ago

An ice skater spins at 2.5 rev/s when his arms are extended. He draws his arms in and spins at 10.0 rev/s. By what factor does h

Rainbow [258]

Answer:

The moment of inertia decreased by a factor of 4

Explanation:

Given;

initial angular velocity of the ice skater, ω₁ = 2.5 rev/s

final angular velocity of the ice skater, ω₂ = 10.0 rev/s

During this process we assume that angular momentum is conserved;

I₁ω₁ = I₂ω₂

Where;

I₁ is the initial moment of inertia

I₂ is the final moment of inertia

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Therefore, the moment of inertia decreased by a factor of 4

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3 years ago

John says that the value of the function cos[ω(t + T) + ϕ], obtained one period T after time t, is greater than cos(ωt + ϕ) by 2

Svetllana [295]

Answer:

No one is right

Explanation:

John Case:

The function $cos(\omega t +\phi)$ is defined between -1 and 1, So it is not possible obtain a value $2\pi$ greater.

In addition, if you move the function cosine a T Value, and T is the Period, the function take the same value due to the cosine is a periodic function.

Larry case:

Is you have $f=1+cos(\omega t +\phi)$ , the domain of this is [0,2].

it is equivalent to adding 1 to the domain of the $f=1+cos(\omega t +\phi)$ , and its mean that the function $f=cos(\omega t +\phi)$ , in general, is not greater than $cos(\omega t +\phi)$ .

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3 years ago