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ra1l [238]
3 years ago
15

A book rest on a table. The force of gravity pulls down on the book 20 newton’s. What prevents the book from accelerating downwa

rd at 9.8 m/s2
Physics
1 answer:
valentina_108 [34]3 years ago
7 0

Answer:

the push of the table on the book

Explanation:

There are two forces acting upon the book.

First force - the Earth's gravitational pull ( a downward force)

Second force - the push of the table on the book ( referred as a normal force) (pushes upward on the book.)

These two forces are of equal magnitude and in opposite directions (20 N)

Therefore they balance each other

The book is said to be at equilibrium state without been subjected to a acceleration

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Explain in 2-3 sentences how a genotype determines a phenotype! <br> Will give b to the best one
allochka39001 [22]

Answer:

Genotype can be determined by biological tests. Both the genotype and phenotype sounds similar but have differences. The phenotype is determined by an individual’s genotype and expressed genes or by visible trait, for instance, hair color or type, eye color body shape, and height. We are all unique. Even monozygotic twins, who are genetically identical, always have some variation in the way they look and act. This uniqueness is a result of the interaction between our genetic make-up, inherited from our parents, and environmental influences from the moment we are conceived.

4 0
3 years ago
Usually the force of gravity on electrons is neglected. To see why, we can compare the force of the Earth’s gravity on an electr
miv72 [106K]

Answer:

6.4\cdot 10^{-15} N

Explanation:

The electric force exerted on the electron is given by:

F=qE

where

q=1.6\cdot 10^{-19}C is the magnitude of the electron charge

E = 40000 V/m is the electric field

Substituting,

F=(1.6\cdot 10^{-19} C)(40000 V/m)=6.4\cdot 10^{-15} N

By comparison, the gravitational force exerted on the electron is:

F=mg

where

m=9.10939\cdot 10^{-31} kg is the mass of the electron

g = 9.8 m/s^2 is the acceleration due to gravity

Substituting,

F=(9.10939\cdot 10^{-31} kg)(9.8 m/s^2)=8.93\cdot 10^{-30}N

6 0
4 years ago
In a weak acid solution, _____.
erastovalidia [21]

Answer:

A)

Explanation:

8 0
3 years ago
Question 15
lozanna [386]

Answer:

Time use of cellphone times 3 hours before sleep.

Explanation:

It is scientifically proven that cell-phone use before bed can disturb your sleep. The blue light can cause your brain to release chemicals that associate with staying awake or even waking up. So measure the hours or minutes you use your phone 3 hours before you go to sleep.

8 0
3 years ago
A ball has m=10 kg and v=10 m/s. It has the same momentum as which of the following?
crimeas [40]

Answer:

Choice d. All three balls listed in choice a, b, and c have a momentum of 100\; \rm kg \cdot m \cdot s^{-1} each, same as that of the 10\; \rm kg ball moving at 10\; \rm m \cdot s^{-1}. Assumption: all four balls are moving in the same direction.

Explanation:

The momentum p of an object is equal to the product of its mass m and its velocity v.

Momentum of a 10\; \rm kg ball moving at 10\; \rm m \cdot s^{-1}:

p = m \cdot v = 10\; \rm kg \times 10\; \rm m \cdot s^{-1} = 100\; \rm kg \cdot m \cdot s^{-1}.

Similarly:

  • Momentum of the ball in choice a: 100 \; \rm kg \times 1\; \rm m \cdot s^{-1} = 100\; \rm kg \cdot m\cdot s^{-1}.
  • Momentum of the ball in choice b: 5 \; \rm kg \times 20\; \rm m \cdot s^{-1} = 100\; \rm kg \cdot m\cdot s^{-1}.
  • Momentum of the ball in choice c: 2 \; \rm kg \times 50\; \rm m \cdot s^{-1} = 100\; \rm kg \cdot m\cdot s^{-1}.

Hence the conclusion that these balls have the same momentum.

7 0
3 years ago
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