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Zina [86]
3 years ago
13

I just need help with these seven!

Physics
1 answer:
Anna [14]3 years ago
5 0
21. light changes its direction when travelling through a new medium because denser mediums have a higher angle of refraction.
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Which of the following characteristics of Earth's crust is likely to contribute to geological events?
olganol [36]

Answer:A

Explanation:

The crust Of The earth's has plates boundaries,when the layers that forms to boundaries glide on each other, vibrations occur which are known as earthquakes

8 0
3 years ago
Earth has a mass of 5,970,000,000,000,000,000,000,000 kg. How would
mr Goodwill [35]

Answer:

5.97×10^24 kg

Explanation:

thats how it is expressed

7 0
3 years ago
This is the normal nucleotide sequence on a DNA strand: A-C-T-G-G-A-T what is a subtituction?
Sunny_sXe [5.5K]
A is the answer to this question...
3 0
4 years ago
Read 2 more answers
A ball is dropped from rest and falls to the floor. The initial gravitational potential energy of the ball-Earth-floor system is
Cloud [144]

Answer:

The mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.

Explanation:

It is given that,

Initial gravitational potential energy of the ball-Earth-floor system is 10 J.

The ball then bounces back up to a height where the gravitational potential energy is 7 J.

Let U is the mechanical energy of the ball-Earth-floor system the instant the ball left the floor. Due to the conservation of energy, the mechanical energy is equal to difference between initial gravitational potential energy and the after bouncing back up to a height.

Initial mechanical energy is 10 + 0 = 10 J

Mechanical energy just before the collision is 0 + 10 = 10 J

Final mechanical energy, 7 + 0 = 7 J

Hence, the mechanical energy of the ball-Earth-floor system the instant the ball left the floor is 7 Joules.

4 0
3 years ago
A ladder of length 10 is leaning against a wall. The vertical wall is frictionless while the horizontal surface is rough. The an
bogdanovich [222]

Answer:

105.1N

Explanation:

According to the newton second law

\sum F_x = ma_x\\F_m - F_f = ma_x\\

Since the acceleration is zero, then;

F_m - F_f = 0\\Fm = F_f\\

Since;

F_m = mg sin \theta, \  hence \ F_f = mg sin \theta

Given the following

mass of ladder m = 14kg

acceleration due to gravity g = 9.8m/s²

θ = 50°

Substitute

F_f = 14(9.8)sin50\\F_f = 14(7.5072)\\F_f = 105.1N\\

Hence the magnitude of the friction force (in N) exerted on the ladder in the point of contact with the horizontal surface is 105.1N

8 0
3 years ago
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