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2 years ago

PLEASE REAL ANSWERS IM SUPER BEHIND

Physics

1 answer:

natima [27]2 years ago

8 0

Answer:

25000W

Explanation:

Kinetic Energy, EK=(1/2)mv2. Energy is conserved, so the work done by the brakes, W, must be equal to the change in kinetic energy of the car, ∆EK. Therefore: W = ∆EK = (1/2)1000(152-52) = 0.51000200 = 100000 = 1*105J. Since power P = W/T, the average power output of the brakes is equal to the total work done by the brakes over the time that the brakes are applied for, therefore: P = 100000/4 = 25000W.

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Which object has the most gravitational potential energy?

Kipish [7]

Answer: An 8 kg book at a height of 3 m has the most gravitational potential energy.

Explanation:

Gravitational potential energy is the product of mass of object, height of object and gravitational field.

So, formula to calculate gravitational potential energy is as follows.

U = mgh

where,

m = mass of object

g = gravitational field = $9.81 m/s^{2}$

h = height of object

(A) m = 5 kg and h = 2m

Therefore, its gravitational potential energy is calculated as follows.

$U = mgh\\= 5 kg \times 9.81 m/s^{2} \times 2 m\\= 98.1 J (1 J = kg m^{2}/s^{2})$

(B) m = 8 kg and h = 2 m

Therefore, its gravitational potential energy is calculated as follows.

$U = mgh\\= 8 kg \times 9.81 m/s^{2} \times 2 m\\= 156.96 J (1 J = kg m^{2}/s^{2})$

(C) m = 8 kg and h = 3 m

Therefore, its gravitational potential energy is calculated as follows.

$U = mgh\\= 8 kg \times 9.81 m/s^{2} \times 3 m\\= 235.44 J (1 J = kg m^{2}/s^{2})$

(D) m = 5 kg and h = 3 m

Therefore, its gravitational potential energy is calculated as follows.

$U = mgh\\= 5 kg \times 9.81 m/s^{2} \times 3 m\\= 147.15 J (1 J = kg m^{2}/s^{2})$

Thus, we can conclude that an 8 kg book at a height of 3 m has the most gravitational potential energy.

3 0

2 years ago

What is the condition for the machine to be perfect?

Roman55 [17]

I’m not really sure

8 0

2 years ago

Read 2 more answers

900n pushes a wedge 0.10 m into a log, if the work done on the log is 50j what is the efficiency of the wedge

mariarad [96]

Answer:

100

Explanation:

mark me brainliest

7 0

2 years ago

Discuss how does a Van de Graaff generator works?

Svetllana [295]

Answer:

How does a Van de Graaff generator works?

A Van de Graaff generator pulls electrons from the Earth, moves them along a belt and stores them on the large sphere. These electrons repel each other and try to get as far away from each other as possible, spreading out on the surface of the sphere. ... It provides a convenient path for electrons to move to the ground.

source-

scienceworld.ca

5 0

2 years ago

The cable of a crane is lifting a 950 kg girder. The girder increases its speed from 0.25 m/s to 0.75 m/sin a distance of 5.5m

Umnica [9.8K]

Explanation:

a) How much work is done by gravity?

w = f x d
w = 950 x 10 x 5.5 = 52250j

b) How much work is done by tension?

v²=u²+2as
0.75²=0.25²+2a x5.5
0.56=0.06+2a x5.5
2a x5.5 = 0.56 - 0.06
2a x 5.5 =0.5
11a=0.5
a = 0.5/11 = 0.05m/s²

w = f x d

w = 950 x 0.05 x 5.5 = 261.25j

7 0

2 years ago