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Yuliya22 [10]
2 years ago
6

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

y rises a vertical distance of 6.89 cm. What was the initial speed of the bullet?
a. 0.38 km/s
b. 0.44 km/s
c. 0.50 km/s
d. 0.54 km/s
e. 0.024 km/s
Physics
1 answer:
Stella [2.4K]2 years ago
8 0

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

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Answer:

3.24×10⁸ J, or 324 MJ

Explanation:

"kWh" is a kilowatt-hour.  It's the energy used by 1 kilowatt of power after one hour.

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3 0
2 years ago
А
timurjin [86]

Answer:

i hope it will be useful for you

Explanation:

F=5.6×10^-10N

R=93cm=0.93m

let take m1 and m2 =m²

according to newton's law of universal gravitation

F=m1m2/r²

F=m²/r²

now we have to find masses

F×r²=m²

5.6×10^10N×0.93m=m²

5.208×10^-9=m²

taking square root on b.s

√5.208×10^-9=√m²

so the two masses are m1=7.2×10^-5

and m2=7.2×10^-5

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a student balances a 1.5kg of broom by placing her finger 1.4m from the end of the broom handle. How far from the broom handle w
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The broom handle that she have to balance if she hung a 400g mass from the end of the broom handle is 5.24m

This problem is centered on moment. Moment is the turning effect of a force about a point. It is expressed as:

Moment = Force× Distance

According to principle of moment, the sum of clockwise moment is equal to sum of anticlockwise moment at shown

M1d1 = M2d2

Given the following

M1 = 1.5kg

d1 = 1.4m

M2 = 400g = 0.4kg

d2 is required

Substitute

1.5(1.4) = 0.4d2

2.1 = 0.4d2

d2 = 2.1/0.4

d2 = 5.24m

Hence the broom handle that she have to  if she hung a 400g mass from the end of the broom handle is 5.24m

Learn more here: brainly.com/question/21945515

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