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Sophie [7]
3 years ago
15

What do you understand by ?efficiency of a machine is 70%​

Physics
1 answer:
tatuchka [14]3 years ago
8 0

Explanation:

The efficiency of a machine is 70% means 30% of the applied force is wasted in overcoming friction and 70% of the applied force is used to do the work

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A body is projected vertically upwards with a speed 100 m/s from the ground then distance it covers in its last second of its up
Valentin [98]

The distance travelled by the body on last second of its upwards journey is 4.935m

What is projectile motion?

A projectile is an object or particle that is launched toward the surface of the Earth and moves along a curved path only under the influence of gravity.

To solve this question, consider the horizontal distance to be H and

distance traveled by the body in the last second be d

H=U^{2} /2g

H=100^{2} /2*9.8

H=510.2m

Now time taken to reach a height of

510.2 m= \sqrt[n]{2H/g}

=10.2 seconds

Now,

s=ut+1/2gt^{2}

H-d= (100)(t-1)-1/2g(t-1)^{2}

510.2-d=100*9.2-1/2*9.8*9.2^{2}

d=4936m

So, the correct answer is '4.936m'.

To know more about projectile motion visit:

brainly.com/question/11049671

#SPJ4

8 0
2 years ago
4. A net force of 15 N is exerted on a book to cause it to accelerate at a rate of 5 m/s2. Determine the mass of the
kenny6666 [7]

Answer:

<h2>3 kg </h2>

Explanation:

The mass of an object given it's force and acceleration can be found by using the formula

m =  \frac{f}{a}  \\

f is the force

a is the acceleration

From the question we have

m =  \frac{15}{5}  = 3 \\

We have the final answer as

<h3>3 kg</h3>

Hope this helps you

4 0
2 years ago
An object moving 20 m/s
yan [13]

Answer:

<u>We are given:</u>

initial velocity (u) = 20m/s

acceleration (a) = 4 m/s²

time (t) = 8 seconds

displacement (s) = s m

<u />

<u>Solving for Displacement:</u>

From the seconds equation of motion:

s = ut + 1/2 * at²

replacing the variables

s = 20(8) + 1/2 * (4)*(8)*(8)

s = 160 + 128

s = 288 m

7 0
3 years ago
14. When incoming light rays strike a flat, plane mirror at an
Mariulka [41]

Answer:

close to the mirrors surface

Explanation:

this is because angle of incidence equals angle of reflection

3 0
3 years ago
What adaptation does a wood frog have that enable it to survive in deciduous forest ?
sweet [91]

Wood frogs have this adaptation where they accumulate urea in their bodies and convert their liver glycogen to glucose to act as cryoprotectants. This prevents the formation of ice crystals in their bodies that could cause damage cells during freezing in winter.  

5 0
3 years ago
Read 2 more answers
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