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1 year ago

You carry a 20 N bag of dog food up a 6.0 m flight of stairs. How much work was done?

1 answer:

8 0

Answer:
120 J

Explanation:

Formula Of Work= Work= Force x Displacement

Work= 20 N x 6.0

Work= 120 Joules

The reason I put joules because the Unit of work is joules

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How much work is done in lifting a 6 kg object from the ground to a height of 4m?

Gekata [30.6K]

W=mgh W=(6)(9.8)(4) W= 235.2J

8 0

3 years ago

PLEASE HELP!!!!!!! MT TIME FOR MY TEST IS ALMOST OVER!!!

pav-90 [236]

Answer:

50 N

Explanation:

Let the natural length of the spring = L

100 = k(40 - L) (1)

200 = k(60 - L) (2)

(2)/(1): 2 = (60 - L)/(40 - L)

60 - L = 2(40 - L)

60 - L = 80 - 2L

2L - L = 80 - 60

L = 20

Sub it into (1):

100 = k(40 - 20) = 20k

k = 100/20 = 5 N/in

Now

X = k(30 - L) = 5(30 - 20) = 50 N

3 0

2 years ago

A 1 036-kg satellite orbits the Earth at a constant altitude of 98-km. (a) How much energy must be added to the system to move t

Veronika [31]

Answer:

a) The Energy added should be 484.438 MJ

b) The Kinetic Energy change is -484.438 MJ

c) The Potential Energy change is 968.907 MJ

Explanation:

Let 'm' be the mass of the satellite , 'M'(6× $10^{24}$ be the mass of earth , 'R'(6400 Km) be the radius of the earth , 'h' be the altitude of the satellite and 'G' (6.67× $10^{-11}$ N/m) be the universal constant of gravitation.

We know that the orbital velocity(v) for a satellite -

v= $\sqrt{\frac{Gmm}{R+h} }$ [(R+h) is the distance of the satellite from the center of the earth ]

Total Energy(E) = Kinetic Energy(KE) + Potential Energy(PE)

For initial conditions ,

h = $h_{i}$ = 98 km = 98000 m

∴Initial Energy ( $E_{i}$ ) = $\frac{1}{2}$ m $v^{2}$ + $\frac{-GMm}{(R+h_{i} )}$

Substituting v= $\sqrt{\frac{GMm}{R+h_{i} } }$ in the above equation and simplifying we get,

$E_{i}$ = $\frac{-GMm}{2(R+h_{i}) }$

Similarly for final condition,

h= $h_{f}$ = 198km = 198000 m

∴Final Energy( $E_{f}$ ) = $\frac{-GMm}{2(R+h_{f}) }$

a) The energy that should be added should be the difference in the energy of initial and final states -

∴ ΔE = $E_{f}$ - $E_{i}$

= $\frac{GMm}{2}$ ( $\frac{1}{R+h_{i} }$ - $\frac{1}{R+h_{f} }$ )

Substituting ,

M = 6 × $10^{24}$ kg

m = 1036 kg

G = 6.67 × $10^{-11}$

R = 6400000 m

$h_{i}$ = 98000 m

$h_{f}$ = 198000 m

We get ,

ΔE = 484.438 MJ

b) Change in Kinetic Energy (ΔKE) = $\frac{1}{2}$ m[ $v_{f} ^{2}$ - $v_{i} ^{2}$ ]

= $\frac{GMm}{2}$ [ $\frac{1} {R+h_{f} }$ - $\frac{1} {R+h_{i} }$ ]

= -ΔE

= - 484.438 MJ

c) Change in Potential Energy (ΔPE) = GMm[ $\frac{1}{R+h_{i} }$ - $\frac{1}{R+h_{f} }$ ]

= 2ΔE

= 968.907 MJ

3 0

3 years ago

It takes you 5 min to walk with an average velocity of .75 m/s to the north from the parking lot to the entrance of the amusemen

skad [1K]

A displacement is a vector quantity that takes into account the shortest distance from the starting point to the endpoint.

The given above gave a time interval in minutes which needs to be converted to seconds. Given that each minute is 60 seconds, 5 minutes equal 300 seconds. To determine the distance, multiply time with speed. The product is 225 m.

Thus, the displacement is 225 m.

3 0

3 years ago

Two forces F1 = -7.90i + 5.40j and F2 = 9.00i + 7.60j are acting on an object with a mass of m = 6.30 kg. The forces are measure

IceJOKER [234]

Answer:

Propotionality is important

Explanation:

7 0

2 years ago