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3 years ago

13

William tell shoots an apple from his son's head. the speed of the 130-g arrow just before it strikes the apple is 24.8 m/s, and

at the time of impact it is traveling horizontally.

1 answer:

shtirl [24]3 years ago

4 0

The kinetic energy of the arrow at that instant is 40 joules.

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Which of the following is not a type of plate boundary

Katarina [22]

Subduction zone is not a plate boundary.

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4 years ago

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Which effect has been useful (and successful) in the search for and identification of black holes in the universe

kvasek [131]

Answer:

Detection of x-rays from a binary star undergoing mass exchange, where mass of component star can be determined.

4 0

2 years ago

What is the mass of a substance that has a density of 5g/ml and the volume of 3ml

Lina20 [59]

Answer:

m= 15g/0.015 kg

Explanation:

density=mass/volume

or, 5g/ml=m/3ml

m= 15 g

3 0

3 years ago

A 7.91g bullet is fired into a 1.52-kg ballistic pendulum initially at rest and becomes embedded in it. The pendulum subsequentl

Stella [2.4K]

Answer:

D

Explanation:

By law of conservation of momentum:

momentum before collision = momentum after collision

$m_{1} u_1 + m_2 u_2 = m_1 v_1 + m_2 v_2\\ m_1 = mass of bullet\\u_1 = initial speed of bullet\\m_2 = mass of pendulum\\u_2 = initial speed of pendulum\\v_1 = final speed of bullet\\v_2 = final speed of pendulum$

Initial speed of bullet is unknown whereas initial speed of pendulum will be zero as it was at rest.

Final speed of bullet and pendulum will be equal as bullet is embedded in pendulum and both moves together a vertical distance of 6.89cm.

Using third equation of motion:

$2 a S = v_{f}^2 - v_{i}^2$

where:

$a = -g = acceleration due to gravity = 9.8 m/s^2 ( for vertical motion)\\S = h = 6.89cm = Vertical height or distance it covers\\v_f = final speed = 0 (after covering 6.89cm)\\v_i = initial speed (unknown)$

Thus by placing values $v_i = 1.1620 m/s$

this speed will be final speed of collision for the calculation of initial speed of bullet.

Putting values:

$(7.91) * x + (1.52*10^3) * 0 = (7.91 + 1.52*10^3) * 1.162\\7.91 x = 1775.431\\x = 224m/s$

This 224m/s = 0.224Km/s which is closest to D

8 0

3 years ago

A bicyclist is traveling at a speed of 20.0 m/s as he approaches the bottom of a hill. He decides to coast up the hill and stops

Rudiy27

Answer:

Vertical height of the hill, h = 20.4 meters

Explanation:

Given that,

Speed of the bicyclist, v = 20 m/s

To find,

The vertical height of the hill.

Solution,

Let h is the height of the hill. When he approaches the bottom of the hill, the loss in kinetic energy is equal to the gain in potential energy. Using the conservation of energy as,

$\dfrac{1}{2}mv^2=mgh$

$h=\dfrac{v^2}{2g}$

$h=\dfrac{(20)^2}{2\times 9.8}$

h = 20.4 meters

Therefore, the vertical height of the hill is 20.4 meters. Hence, this is the required solution.

5 0

3 years ago