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Alenkinab [10]
3 years ago
7

500 J of work are done in 4 seconds to lift a 40 kg box to the top of a high shelf. How much power was required to complete the

lift?
Physics
1 answer:
Artemon [7]3 years ago
5 0

Answer:

125 W

Explanation:

Power = work / time

P = 500 J / 4 s

P = 125 W

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Speed and Motion you went from the starting line to the finish line at different rates. If you repeated the activity while carry
Phantasy [73]

Answer:

It will cause kinetic energy to increase.

Explanation:

Given that Speed and Motion you went from the starting line to the finish line at different rates.

If you repeated the activity while carrying weights but keeping your times the same, the weight carried will add up to the mass of the body.

And since Kinetic energy K.E = 1/2mv^2

Increase in the mass of the body will definitely make the kinetic energy of the body to increase.

Since the time is the same, that means the speed V is the same.

Weight W = mg

m = W/g

The new kinetic energy will be:

K.E = 1/2(M + m)v^2

This means that there will be increase in kinetic energy.

3 0
3 years ago
Consider an elevator with a table and a book on top of the table. The mass of the table is 10kg and the mass of the book is 2kg.
Step2247 [10]

Newton's second law allows us to find the force of the block on the table is 126 N

Newton's second law says that the net force is proportional to the product of the mass and the acceleration of the body

                Σ F = m a

Where the bold letters indicate vectors, m is the mass and the acceleration of the body

A free body diagram is a diagram where the forces are represented without the details of the bodies, in the attached we can see a free body diagram of the system.

Let's start by finding the acceleration of the elevator with kinematics  

                 v = v₀ + a t

                 a = \frac{v-v_o}{a}  

Where v and v₀ are the current and initial velocity, respectively, at acceleration and t is the time

                 a = \frac{8-1}{2}

                 a = 3.5 m / s²

Let's write Newton's second law for each body

The book

                N₂ - W₂ + N₁ = m a

               

Table

                N₁ - W₁ - W₂ = M a

                W₁ = Mg

                W₂ = mg

                N₁ = (M + m) g + M a

                N₁ = (10 + 2) 9.8 + 10 3.5

                N₁ = 152.6 N

This is the reaction of the earth to the support of the block and the table

               N₂ = ma + m g  - N₁

               N₂ = m ( a +g) - N₁  

               N₂ = 2 (3.5 + 9.8) - 152.6

               N₂ = 26.6 - 152.6

               N₂ = -126 N

The negative sign indicates that the direction is opposite to the one assigned, this is the action of the block on the table.

In conclusion using Newton's second law we can find the forces of the block on the table is 126 N

Learn more here: brainly.com/question/19860811

4 0
2 years ago
What is the approximate value of the gravitational force between a 73 kg astronaut and a 7.1×104 kg spacecraft when they're 89 m
Luden [163]

Answer:

F = 4.3671 * 10^{-8}\ Newtons

Explanation:

The gravitational force between two corpses is given by the following equation:

F = GMm/d^2

Where F is the force, G is the gravitational constant

(G = 6.67408*10^{-11}\ m^3kg^{-1}s^{-2}), M and m are the masses of the corpses and d is the distance between them.

So we have that:

F = 6.67408*10^{-11} * 7.1*10^4 * 73/89^2

F = 4.3671 * 10^{-8}\ Newtons

5 0
3 years ago
at the extact same time, youj drop a piece of notebook paper and your science out the window. the science book hit first? why?
jeyben [28]
The piece of paper has less mass and will glide down the window, whereas the textbook will go straight to the ground. Since the textbook has more mass and less ways of it being able to 'glide' the textbook will hit the ground first.
8 0
3 years ago
A low-pass first-order instrument has a time constant of 20 ms. find the frequency, in hertz, of the input at which the output w
Vladimir [108]
?????????????????????????????
8 0
3 years ago
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