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2 years ago

Question 2 (5 points)

Physics

1 answer:

Helen [10]2 years ago

5 0

Answer: A) All matter and energy were contained inside the small point.

Explanation: The theory that all matter and energy in the universe expanded from one condensed point (this is called the big bang theory) is the generally accepted explanation of the origins of our universe. Thought increasing amounts of doubt have been cast upon this theory in the last decade.

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What is the temperature inside of a tree?

Oliga [24]

It’s 21 c it all on the weather outside but most of the time it’s on 21

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3 years ago

A 5.00 g object moving to the right at 20.0 cm/s makes an elastic head-on collision with a 10.0 g object that is initially at re

marusya05 [52]

Answer: a) 6.67cm/s b) 1/2

Explanation:

According to law of conservation of momentum, the momentum of the bodies before collision is equal to the momentum of the bodies after collision. Since the second body was initially at rest this means the initial velocity of the body is "zero".

Let m1 and m2 be the masses of the bodies

u1 and u2 be their velocities respectively

m1 = 5.0g m2 = 10.0g u1 = 20.0cm/s u2 = 0cm/s

Since momentum = mass × velocity

The conservation of momentum of the body will be

m1u1 + m2u2 = (m1+m2)v

Note that the body will move with a common velocity (v) after collision which will serve as the velocity of each object after collision.

5(20) + 10(0) = (5+10)v

100 + 0 = 15v

v = 100/15

v = 6.67cm/s

Therefore the velocity of each object after the collision is 6.67cm/s

b) kinectic energy of the 10.0g object will be 1/2MV²

= 1/2×10×6.67²

= 222.44Joules

kinectic energy of the 5.0g object will be 1/2MV²

= 1/2×5×6.67²

= 222.44Joules

= 111.22Joules

Fraction of the initial kinetic transferred to the 10g object will be

111.22/222.44

= 1/2

3 0

3 years ago

Find the net work W done on the particle by the external forces during the motion of the particle in terms of the initial and fi

steposvetlana [31]

Answer:

$W=K_f-K_i$

Explanation:

The work done on a particle by external forces is defined as:

$W=\int\limits^{r_f}_{r_i} {F\cdot dr} \,$

According to Newton's second law $F=ma$ . Thus:

$W=\int\limits^{r_f}_{r_i}{ma\cdot dr} \,\\$

Acceleration is defined as the derivative of the speed with respect to time:

$W=m\int\limits^{r_f}_{r_i}{\frac{dv}{dt}\cdot dr} \,\\\\W=m\int\limits^{r_f}_{r_i}{dv \cdot \frac{dr}{dt}} \,$

Speed is defined as the derivative of the position with respect to time:

$W=m\int\limits^{v_f}_{v_i} v \cdot dv \,$

Kinetic energy is defined as $K=\frac{mv^2}{2}$ :

$W=m\frac{v_f^2}{2}-m\frac{v_i^2}{2}\\W=K_f-K_i$

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2 years ago

Gabriella got a burn on her arm from a chemical spill and rinsed the area thoroughly with water. Which piece of safety equipment

ioda

I believe it she should use the first aid kit next

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2 years ago

Read 2 more answers

Each year, an average person in the United States is exposed to a radiation level of _____.

Anna11 [10]

Answer:

The correct answer is 0,2 rems

Explanation:

People are exposed to natural sources of radiation all the time. According to recent estimates, the average person in the United States receives an effective dose of approximately 3 mSv per year of natural radiation, which is equivalent to 0.3 rems. This amount includes cosmic radiation from outer space and is average because it varies depending on the region people are in.

The amount of radiation for a chest x-ray of an adult (0.01 rems) is approximately equal to 10 days of natural radiation to which we are all exposed every day.

Have a nice day!

3 0

2 years ago