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7nadin3 [17]
3 years ago
15

A construction worker puts 20J of energy in to one strike of his hammer on the head of a nail. The energy transferred to driving

d nail in to d wood is 8J. What is d efficiency of d construction worker's hammering?​
Physics
2 answers:
KengaRu [80]3 years ago
4 0

Answer:

The efficiency can be found using the formula ;

efficiency=energy output divided by energy input ×100%.

efficiency=8.0j÷ 20j × 100%

efficiency=0.4 ×100%

efficiency=40%.

the efficiency of the hammer strike was 40%. vibration and heating of the nail are two possible reasons for the energy loss.

Slav-nsk [51]3 years ago
3 0

Answer:

efficiancy=40 percent

Explanation:

efficiency=energy output/energy input×100

efficiancy=8J/20J×100

efficiancy=0.4×100

efficiancy=40 percent

Mark brianliest if my answer suit your question..

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A volcano erupts and launches a chunk of hot magma horizontally with a speed of 252 m/s. The magma travels a horizontal distance
ArbitrLikvidat [17]

Answer:

The value is v_y  =  -48.61 \ m/s

Explanation:

From the question we are told that

   The horizontal speed is  u_x  = 252 \  m/s

    The horizontal distance is  d = 1250 \ m

Generally the time taken by the hot magma in air before landing is mathematically represented as

       t = \frac{d}{u_x}

=>    t = \frac{ 1250 }{252}

=>    t = 4.96 \  s

Generally the initial vertical velocity of the magma when it was lunched is  

    u_y = 0 \ m/ s

Then the final velocity of the magma when it hits the ground is mathematically represented s

       - v_y  =  u_y + gt

Here the negative sign mean that the direction of the velocity is towards the negative y -axis

So  

        - v_y  =  48.61 \ m/s

=>     v_y  =  -48.61 \ m/s

7 0
3 years ago
Convert the number from scientific into standard notation: 5.9 x 10-2
guapka [62]
Move the decimal point to:
Left : (if the exponent of ten is a negative number -) ... OUR CASE HERE (-2)
or to
Right : (if the exponent is positive +).

You should move the point as many times as the exponent indicates.
Do not write the power of ten anymore.

So, standard form is:
Two points to the left {Exponent of Ten is Negative (-2)}
0.059 ... (without the 10)
6 0
3 years ago
A vertical spring has a length of 0.25 m when a 0.175 kg mass hangs from it, and a length of 0.775 m when a 2.075 kg mass hangs
Contact [7]

Answer:

A) 35.5N/m b) 20.1cm

Explanation:

Using Hooke's law;

F = Ke where F is the weight of the object = mass of the object in kg * acceleration due to gravity in m/s^2 and k if the force constant of the spring in N/m and e is the extension of the spring which original length of the spring - new length after extension in meters

For the first body, m*g = K * (0.25- li)

Where li is the initial length of the spring

0.175*9.81 = k(0.25-li)

1.72 = k(0.25-li) as equation 1

For the second body, m *g = K* ( 0.775-li)

2.075*9.81 = k (0.775-li) equation 2

20.36 = k(0.775-li)

Make li subject of the formula;

li = 0.775 - 20.36/k

Substitute for li in equation 1

1.72 = k(0.25- (0.775 - 20.36/k))

1.72 = k ( 0.25 - 0.775 + 20.36/k)

Open the bracket with k

1.72 = 0.25k - 0.775k + 20.36 (since k cancel k)

Collect the like terms:

1.72 - 20.36 = - 0.525k

- 18.64 = -0.525k

Divide both side by -0.525

-18.64/-0.525 = -0.525/-0.525k

K = 35.5N/m

B) substitute for k in using

li = 0.775 - 20.36/k

li = 0.775 - 20.36/35.5

li = 0.775 - 0.574

li = 0.201 in meters

li = 0.201 * 100 centimeters = 20.1cm

4 0
3 years ago
True or false energy is always lost in a circuit
Llana [10]

Explanation:

Electrons will gain energy as they are "pushed" from different points in the circuit. This energy is then lost when the electrons flow through circuit components such as a light bulb.

7 0
2 years ago
What is the thermal energy of an object?
mr Goodwill [35]
The thermal energy of an object is the energy contained in the motion and vibration of its molecules. Thermal energy is measured through temperature. The energy contained in the small motions of the object's molecules can be broken up into a combination of microscopic kinetic energy and potential energy.
5 0
3 years ago
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