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ira [324]
3 years ago
9

A rock is thrown downward from the top of a 36.2-m-tall tower with an initial speed of 13 m/s. Assuming negligible air resistanc

e, what is the speed of the rock just before hitting the ground
Physics
1 answer:
vekshin13 years ago
4 0

Explanation:

u = 13m/s

s = 36.2m

a = 9.81m/s² (positive because it is acting on the same direction as the velocity)

Using Kinematics, we have v² = u² + 2as = (13)² + 2(9.81)(36.2) = 879.244m²/s². => v = 29.65m/s.

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Suppose the coefficient of static friction between a quarter and the back wall of a rocket car is 0.383. At what minimum rate wo
djverab [1.8K]

Answer:

25.59 m/s²

Explanation:

Using the formula for  the force of static friction:

f_s = \mu_s N --- (1)

where;

f_s = static friction force

\mu_s = coefficient of static friction

N = normal force

Also, recall that:

F = mass × acceleration

Similarly, N = mg

here, due to min. acceleration of the car;

N = ma_{min}

From equation (1)

f_s = \mu_s ma_{min}

However, there is a need to balance the frictional force by using the force due to the car's acceleration between the quarter and the wall of the rocket.

Thus,

F = f_s

mg = \mu_s ma_{min}

a_{min} = \dfrac{mg }{ \mu_s m}

a_{min} = \dfrac{g }{ \mu_s }

where;

\mu_s = 0.383 and g = 9.8 m/s²

a_{min} = \dfrac{9.8 \ m/s^2 }{0.383 }

\mathbf{a_{min}= 25.59 \ m/s^2}

3 0
2 years ago
A 580-turn solenoid is 18 cm long. The current in it is 36 A. A straight wire cuts through the center of the solenoid, along a 2
Karolina [17]

Answer:

F = 0.078N

Explanation:

In order to calculate the magnitude of the force on the wire you first calculate the magnitude of the magnetic field generated by the solenoid, by using the following formula:

B=\frac{\mu_oNi}{L}         (1)

μo: magnetic permeability of vacuum = 4π*10^-7 T/A

N: turns of the solenoid = 580

i: current in the solenoid = 36A

L: length of the solenoid = 18cm = 0.18m

You replace the values of all parameters in the equation (1):

B=\frac{(4\pi*10^{-7}T/A)(580)(36A)}{0.18m}=0.145T

Next, you calculate the force exerted on the wire, by using the following formula:

F=iLBsin\theta         (2)

i: current in the wire = 27A

L: length of the wire that perceives the magnetic field (the same as the radius of the solenoid) = 2.0 cm = 0.02m

θ: angle between wire and the direction of B

B: magneitc field in the solenoid = 0.145T

The direction of the wire are perpendicular to the direction of the magnetic field, hence, the angle is 90°.

You replace the values of the parameters in the equation (2):

F=(27A)(0.02m)(0.145T)sin90\°=0.078N

The magnitude of the force on the wire is 0.078N

8 0
3 years ago
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How are eras and periods of the geologic time scale named?
Natalka [10]

Answer:

mark me brainliest plz

Explanation:

In the early 1800's a system for naming geologic time periods was devised using four periods of geologic time. They were named using Latin root words, Primary, Secondary, Tertiary and Quaternary. ... Keep in mind that this chart is focused on geologic time periods. There are also geologic Eons, Eras, and epochs.

3 0
3 years ago
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Describe a procedure that would increase the potential energy of two magnets if like poles are used. Explain why the energy of t
zalisa [80]

Answer:

If you apply a force to separate 2 opposite poles, the potential energy of the system increases.

5 0
2 years ago
How can a cyclist minimize friction as he or she rides? A. by increasing the weight of the bike B. by increasing the tread on hi
jek_recluse [69]
B I believe is the answer!

Hope this helps and have a great day!!!
6 0
3 years ago
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