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2 years ago

How can the power of an object required to lift a mass up a height be increased ?

Physics

1 answer:

Paraphin [41]2 years ago

4 0

Decrease the time since power is energy divide by time so decreasing the time will increase the power

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Select all that apply. An acorn falls from a tree. Which of the following statements is true? The force of gravity is acting on

DedPeter [7]

The net force on the acorn is less than the force of gravity.

6 0

3 years ago

Read 2 more answers

The first law of thermodynamics states that ΔE= Q− W . Is this also a statement of the principle of conservation of energy? Yes,

ozzi

Answer:

Yes, the heat that flows into the system is used to change the internal energy of the gas and becomes work done by the piston.

Explanation:

First law of thermodynamics known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another.

The first law of thermodynamics states that the change in internal energy of a system equals the net heat transfer into the system minus the net work done by the system. In equation form, the first law of thermodynamics.

This is the first law of thermodynamics

ΔE= Q− W

ΔE= change internal energy of the system.

Q= heat transfer into the system

And

W= work done by the system.

Rewriting the equation

ΔE= Q− W

Q=ΔE +W

Show that the heat flowing l into the system is transferred to the internal energy of the system and the work done by the piston

So the third option is correct

3 0

2 years ago

A rock falls for 3 seconds. What was its velocity when it hit the ground?

malfutka [58]

Answer:

for this i uploaded i screenshot

Explanation:

5 0

2 years ago

A fairground ride spins its occupants inside a flying saucer-shaped container. If the horizontal circular path the riders follow

Oksana_A [137]

Answer:

a) $\omega=1.36rad/s$

b) $\omega=12.99rpm$

c) $F=705.6N$

Explanation:

a) The angular velocity is related to the centripetal acceleration by the formula $a_{cp}=\omega^2r$ , which for our purposes we will write as:

$\omega=\sqrt{\frac{a_{cp}}{r}}$

Since <em>we want this acceleration to be 1.5 times that due to gravity</em>, for our values we will have:

$\omega=\sqrt{\frac{1.5g}{r}}=\sqrt{\frac{(1.5)(9.8m/s^2)}{(8m)}}=1.36rad/s$

b) 1 rpm (revolution per minute) is equivalent to an angle of $2\pi$ radians in 60 seconds:

$1\ rpm=\frac{2\pi rad}{60s} =\frac{\pi}{30}rad/s$

Which means <em>we can use the conversion factor</em>:

$\frac{1\ rpm}{\frac{\pi}{30}rad/s}=1$

So we have (multiplying by the conversion factor, which is 1, not affecting anything but transforming our units):

$\omega=1.36rad/s=1.36rad/s(\frac{1\ rpm}{\frac{\pi}{30}rad/s})=12.99rpm$

c) The centripetal force will be given by Newton's 2nd Law F=ma, so on the centripetal direction for our values we have:

$F=ma=(48kg)(1.5)(9.8m/s^2)=705.6N$

8 0

2 years ago

A 78 kg skydiver can be modeled as a rectangular "box" with dimensions 24 cm × 35 cm × 170 cm . If he falls feet first, his drag

ANTONII [103]

Answer:

The terminal speed of his is 137.68 m/s.

Explanation:

Given that,

Mass of skydiver = 78 kg

Area of box $A =24\times35=840\ cm$

Drag coefficient = 0.80

Density of air $\rho= 1.2\times kg/m^3$

We need to calculate the terminal velocity

Using formula of drag force

$F_{d} = \dfrac{1}{2}\rho v^2Ac$

Where,

$\rho$ = density of air

A = area

C= coefficient of drag

Put the value into the formula

$78\times9.8=\dfrac{1}{2}\times1.2\times v^2\times24\times10^{-2}\times35\times10^{-2}\times0.80$

$v^2=\dfrac{2\times78\times9.8}{1.2\times24\times10^{-2}\times35\times10^{-2}\times0.80}$

$v=\sqrt{\dfrac{2\times78\times9.8}{1.2\times24\times10^{-2}\times35\times10^{-2}\times0.80}}$

$v=137.68\ m/s$

Hence, The terminal speed of his is 137.68 m/s.

3 0

3 years ago