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3 years ago

6. A person lifts a package weighing 75 N. If she lifts it 1.2 m off the floor,

Physics

1 answer:

balandron [24]3 years ago

7 0

Answer:

90 Joules

Explanation:

75×1.2=90.

i believe it is this

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What can you calculate using the equation P equals W/t

Natalka [10]

WE CALCULATE POWER AND RATE OF DOING WORK IS CALLED POWER

8 0

3 years ago

A jogger accelerates from rest to 4.86 m/s in 2.43 s. A car accelerates from 20.6 to 32.7 m/s also in 2.43 s. (a) Find the magni

Aleonysh [2.5K]

Explanation:

It is given that,

Initially, the jogger is at rest u₁ = 0

He accelerates from rest to 4.86 m, v₁ = 4.86 m

Time, t₁ = 2.43 s

A car accelerates from u₂ = 20.6 to v₂ = 32.7 m/s in t₂ = 2.43 s

(a) Acceleration of the jogger :

$a=\dfrac{v-u}{t}$

$a=\dfrac{4.86\ m/s-0}{2.43\ s}$

a₁ = 2 m/s²

(b) Acceleration of the car,

$a=\dfrac{v-u}{t}$

$a=\dfrac{32.7\ m/s-20.6\ m/s}{2.43\ s}$

a₂ = 4.97 m/s²

(c) Distance covered by the car,

$d_1=u_1t_1+\dfrac{1}{2}a_1t_1^2$

$d_1=0+\dfrac{1}{2}\times 2\times (2.43)^2$

d₁ = 5.904 m

Distance covered by the jogger,

$d_2=u_2t_2+\dfrac{1}{2}a_2t_2^2$

$d_2=20.6\times 2.43+\dfrac{1}{2}\times 4.97\times (2.43)^2$

d₂ = 64.73 m

The car further travel a distance of, d = 64.73 m - 5.904 m = 58.826 m

Hence, this is the required solution.

5 0

2 years ago

Earl is using his hands to hold a metal pan 10 centimeters above a hot burner. How can this scenario be changed to demonstrate c

Olenka [21]

Answer: touch the pan to the burner

Explanation:

There are three modes of heat transfer:

conduction, convection and radiation.

For conduction, the heat transfers from a hot object to a cold object when the two are in contact.

For convection there is bulk motion of fluid occurs which transfers the heat.

For heat transfer by radiation, medium is not required.

Thus, to demonstrate conduction between pan and burner, the pan must touch the burner.

8 0

3 years ago

Read 2 more answers

g A large tank, at 400 kPa and 450 K, supplies air to a converging-diverging nozzle of throat area 4 cm2 and exit area 5 cm2. Fo

mariarad [96]

Answer:

A) ≥ 325Kpa

B) ( 265 < Pe < 325 ) Kpa

C) (94 < Pe < 265 )Kpa

D) Pe < 94 Kpa

Explanation:

Given data :

A large Tank : Pressures are at 400kPa and 450 K

Throat area = 4cm^2 , exit area = 5cm^2

a) Determine the range of back pressures that the flow will be entirely subsonic

The range of flow of back pressures that will make the flow entirely subsonic

will be ≥ 325Kpa

attached below is the detailed solution

B) Have a shock wave

The range of back pressures for there to be shock wave inside the nozzle

= ( 265 < Pe < 325 ) Kpa

attached below is a detailed solution

C) Have oblique shocks outside the exit

= (94 < Pe < 265 )Kpa

D) Have supersonic expansion waves outside the exit

= Pe < 94 Kpa

7 0

3 years ago

A LASIK vision-correction system uses a laser that emits 10-ns-long pulses of light, each with 3.0 mJ of energy. The laser beam

lyudmila [28]

P = energy/t = 0.0025/1E-8 = 250000 W
I(ave) = P/A = 250000/(pi*0.425E-3^2) = 4.4056732E11 W/m^2
I(peak) = 2I(ave) = 8.8113463E11 W/m^2
Electric field E = sqrt(I(peak)*Z0) = 1.8219499E7 V/m, where
free-space impedance Z0 = sqrt(µ0/e0) = 376.73031 ohms

7 0

3 years ago