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3 years ago

A train travels 65 kilometers in 5 hours, and then 61 kilometers in 4 hours. What is its average speed? _______km/hr

Physics

2 answers:

olasank [31]3 years ago

4 0

The trains average speed is 13 km/hr.

Galina-37 [17]3 years ago

4 0

Yes, Average speed equals total distance divided by total time.

Total distance= 65km + 61km= 126 km

Total time= 5h + 4h = 9 h

126km/9h= 14km/h

The trains average speed is 14 km/h

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3 years ago

A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. Half

bekas [8.4K]

Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).

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Half of the kinetic energy of the hammer is transformed into heat in the nail.

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$\frac{1}{2}K.E.=\frac{1}{2}\times 36.125 J=18.0625 J$

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3 years ago

a street light is mounted at the top of a 15 foot pole. A man 6 ft tall walks away from the pole wit a speed of 7 ft/s along a s

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Answer:

16.3 ft/s

Explanation:

Let d=distance

and

x = length of shadow.

Therfore,

x=(d + x)

= 6/15

So,

15x = 6x + 6d

9x = 6d.

x = (2/3)d.

As we know that:

dx=dt

= (2/3) (d/dt)

Also,

Given:

d(d)=dt

= 7 ft/s

Thus,

d(d + x)=dt

= (7/3)d (d/dt)

Substitute, d= 7

d(d + x) = 49/3 ft/s.

Hence,

d(d + x) = 16.3 ft/s.

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3 years ago

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ValentinkaMS [17]

Answer:

because it is from a mathematical combination of SI base units

Explanation:

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3 years ago