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aev [14]
3 years ago
5

PLS HELP! A boy drops a ball from an observation tower. The ball hits the ground in 3.0 s. What is the ball's velocity at the ti

me of impact?
Physics
1 answer:
Levart [38]3 years ago
4 0

Answer:

v = u + at

v = 0 + 9.8 × 3

v = 29.4 m/sec

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Two cars are traveling in the same direction down a highway at 65 miles per hour. What is the relative velocity of the second ca
Levart [38]

Answer:

5 hours

Explanation:

Let the required time be x hours. The time will be the same for both cars.

The cars will cover different distances because they are travelling at different speeds.

<em>D=S×T </em>

The distance travelled by the slower car = 50×x miles.

The distance travelled by the faster car = 58×x miles.

The two distances differ by 40 miles.

58x−50x=40

8x=40

x=5 hours

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A second method:

The difference in the distances is 40 miles

The difference in the speeds is #8mph.

The time to make up the 40 miles= \frac{40}{8}=5 hours

8 0
3 years ago
A centrifuge used in DNA extraction spins at a maximum rate of 7000rpm producing a "g-force" on the sample that is 6000 times th
defon

Answer:

A) a = 73.304 rad/s²

B) Δθ = 3665.2 rad

Explanation:

A) From Newton's first equation of motion, we can say that;

a = (ω - ω_o)/t. We are given that the centrifuge spins at a maximum rate of 7000rpm.

Let's convert to rad/s = 7000 × 2π/60 = 733.04 rad/s

Thus change in angular velocity = (ω - ω_o) = 733.04 - 0 = 733.04 rad/s

We are given; t = 10 s

Thus;

a = 733.04/10

a = 73.304 rad/s²

B) From Newton's third equation of motion, we can say that;

ω² = ω_o² + 2aΔθ

Where Δθ is angular displacement

Making Δθ the subject;

Δθ = (ω² - ω_o²)/2a

At this point, ω = 0 rad/s while ω_o = 733.04 rad/s

Thus;

Δθ = (0² - 733.04²)/(2 × 73.304)

Δθ = -537347.6416/146.608

Δθ = - 3665.2 rad

We will take the absolute value.

Thus, Δθ = 3665.2 rad

8 0
3 years ago
What is the meaning of technology
slamgirl [31]
The exact definition of technology is: The application of scientific knowledge for practical purposes, especially in industry.

The way I would put it is that technology isn’t just electronics, smartphones, and flying cars. Technology is information that people reveal and figure out and this is why it advances. You hear all the time the “advances in technology” and it’s a term that has grown rapidly. It helps businesses to progress, it’s taught people, it’s in some ways beneficial to people’s lives. It has many meanings and really that is technology simply put.
5 0
3 years ago
Problem PageQuestion A cylinder measuring 2.3cm wide and 2.7cm high is filled with gas. The piston is pushed down with a steady
Alexandra [31]
Jehedhdhsh dbdbdbdbdbdbdbebddnsbdb
Dhdhdbdbdbdbdhfhbdbddbdbdbdbdbdbsbsbsbdbdbdb d s DVD’s
8 0
3 years ago
A hot (70°C) lump of metal has a mass of 250 g and a specific heat of 0.25 cal/g⋅°C. John drops the metal into a 500-g calorimet
Gnom [1K]

Answer:

d. 37 °C

Explanation:

m_{m} = mass of lump of metal = 250 g

c_{m} = specific heat of lump of metal  = 0.25 cal/g°C

T_{mi} = Initial temperature of lump of metal = 70 °C

m_{w} = mass of water = 75 g

c_{w} = specific heat of water = 1 cal/g°C

T_{wi} = Initial temperature of water = 20 °C

m_{c} = mass of calorimeter  = 500 g

c_{c} = specific heat of calorimeter = 0.10 cal/g°C

T_{ci} = Initial temperature of calorimeter = 20 °C

T_{f} = Final equilibrium temperature

Using conservation of heat

Heat lost by lump of metal = heat gained by water + heat gained by calorimeter

m_{m} c_{m} (T_{mi} - T_{f}) = m_{w} c_{w} (T_{f} - T_{wi}) +  m_{c} c_{c} (T_{f} - T_{ci}) \\(250) (0.25) (70 - T_{f} ) = (75) (1) (T_{f} - 20) + (500) (0.10) (T_{f} - 20)\\T_{f} = 37 C

6 0
4 years ago
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