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statuscvo [17]
2 years ago
8

A book rests on the shelf of a bookcase. The reaction force to the force of gravity acting on the book is 1. The force of the sh

elf holding the book up. 2. The force exerted by the book on the earth. 3. The weight of the book. 4. The frictional force between book and shelf. 5. None of these.
Physics
2 answers:
Stells [14]2 years ago
8 0

Answer: the force exerted by the book on the earth

Hoochie [10]2 years ago
6 0

Answer:

1. The force of the shelf holding the book up.

Explanation:

The free body diagram of the book is as follows:

1 - The weight of the book towards downwards

2 - The normal force that the shelf exerts on the book towards upwards.

Since the book is at rest, these two forces are equal to each other and according to Newton's Third Law the reaction force to the force of gravity is equal but opposite to the weight of the book. This reaction force is the one that holds the book up on the shelf.

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1) A sound wave with a frequency of 300 hertz is traveling through a medium at a speed of 320 meters/second. What is its wavelen
timurjin [86]
1. The wavelength is the ratio of the wave's speed to its frequency in hertz or 1/s. This is shown below,
                           λ = s / f = (320 m/s)  / (300 1/s) = 1.07 m
The wavelength is approximately 1.07 m.

2. The frequency is the ratio between speed and the wavelength,
                        f = (330 m/s) / 0.45 m = 733.33 hertz

 
5 0
2 years ago
Read 2 more answers
An archer tests various arrowheads by shooting arrows at a pumpkin that is suspended from a tree branch by a rope, as shown to t
erik [133]

Answer:

Bounce 1 ,  pass 3,   emb2

Explanation:

(By the way I am also doing that question on College board physics page) For the Bounce arrow, since it bumps into the object and goes back, it means now it has a negative momentum, which means a larger momentum is given to the object. P=mv, so the velocity is larger for the object, and larger velocity means a larger kinetic energy which would result in a larger change in the potential energy. Since K=0.5mv^2=U=mgh, a larger potential energy would have a larger change in height which means it has a larger angle θ with the vertical line. Comparing with the "pass arrow" and the "Embedded arrow", the embedded arrow gives the object a larger momentum, Pi=Pf (mv=(M+m)V), it gives all its original momentum to the two objects right now. (Arrow and the pumpkin), it would have a larger velocity. However for the pass arrow, it only gives partial of its original momentum and keeps some of them for the arrow to move, which means the pumpkin has less momentum, means less velocity, and less kinetic energy transferred into the potential energy, and means less change in height, less θangle.  So it is  Bounce1, pass3, emb2.  

6 0
2 years ago
The engine on a fighter airplane can exert a force of 105,840 N (24,000 pounds). The take-off mass of the plane is 16,875 kg. (I
FrozenT [24]

Answer:

The acceleration you can get with that engine in your car is around 70,56 (\frac{m}{s^{2} }) or 7,26 (\frac{ft}{s^{2} } ) using 1500kg of mass or 3306 pounds

Explanation:

Using the equation of the force that is:

F=m*a

So, you notice that you know the force that give the engine, so changing the equation and using a mass of a car in 1500 kg or 3306 pounds

a=\frac{F}{m} =\frac{105840 N }{1500 (kg) }

a=\frac{105840 (\frac{kg*m}{s^{2} } )} {1500 kg }

<em> Note: N or Newton units are: \frac{kg * m}{s^{2} }</em>

a= 70,54 \frac{m}{s^{2} }

Also in pounds you can compared

a= \frac{2400  lf }{3 306  lf}

Note: lf in force units are: \frac{lf*ft}{s^{2} }

a=7,26 \frac{ft}{s^{2} }

8 0
2 years ago
a 59kg physics student jumps off the back of her laser sailboat (42kg). after she jumps the laser is found to be travelling at 1
evablogger [386]

From the conservation of linear momentum of closed system,

Initial momentum = final momentum

Mass of the student, M = 59 kg

Mass of the laser boat, m = 42 kg

Initial speed of student + laser boat, u =0

Final speed of laser boat, v = 1.5 m/s

Final speed of the student = V

(M+m) u =M V +m v

0 = (59 kg) V + (42 kg) (1.5m/s)

V = - 1.06 m/s

Thus, the speed of the student is 1.06 m/s in the opposite direction of the motion of boat.

5 0
2 years ago
A projectile is launched from the ground with an initial velocity of 12ms at an angle of 30° above the horizontal. The projectil
netineya [11]

vi^{2}sin2thita/g =12^{2}sin2[30]/9.8=12.7Answer:

Explanation:

range is given as

6 0
2 years ago
Read 2 more answers
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