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3 years ago

What is the pooled variance for the following two samples?

Physics

1 answer:

Snowcat [4.5K]3 years ago

4 0

I think it is B as 168/20

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From the top of the engineering building, you throw a ball vertically upward. the ball strikes the ground 4.00 s later. the engi

anastassius [24]

Equations of the vertical launch:

Vf = Vo - gt

y = yo + Vo*t - gt^2 / 2

Here yo = 35.0m
Vo is unknown
y final = 0
t = 4.00 s
and I will approximate g to 10m/s^2

=> 0 = 35.0 + Vo * 4 - 5 * (4.00)^2 => Vo = [-35 + 5*16] / 4 = - 45 / 4 = -11.25 m/s

The negative sign is due to the fact that the initial velocity is upwards and we assumed that the direction downwards was positive when used g = 10m/s^2.

Answer: 11.25 m/s

5 0

3 years ago

Read 2 more answers

If the change in kinetic energy of a tennis ball hit by the racket

Marrrta [24]

Answer: .36 m

Explanation:

5 0

3 years ago

A toy cannon uses a spring to project a 5.24-g soft rubber ball. The spring is originally compressed by 5.01 cm and has a force

salantis [7]

Answer:

Speed will be equal to 1.40 m/sec

Explanation:

Mass of the rubber ball m = 5.24 kg = 0.00524 kg

Spring is compressed by 5.01 cm

So x = 5.01 cm = 0.0501 m

Spring constant k = 8.08 N/m

Frictional force f = 0.031 N

Distance moved by ball d = 15.8 cm = 0.158 m

Energy gained by spring

$KE=\frac{1}{2}kx^2=\frac{1}{2}\times 8.08\times 0.0501^2=0.0101J$

Energy lost due to friction

$W=Fd=0.031\times 0.158=0.0048J$

So remained energy to move the ball = 0.0101 - 0.0048 = 0.0052 J

This energy will be kinetic energy

$\frac{1}{2}mv^2=0.0052$

$\frac{1}{2}\times 0.00524\times v^2=0.0052$

v = 1.40 m/sec

7 0

3 years ago

• Usain Bolt can run at 10 m/s. If he runs for about 20 seconds, how far around the race track did he go?

yanalaym [24]

Answer:

200metters

Explanation:

because in one second hes going 10 metter in 20 second he will go 20×10=200

4 0

3 years ago

Note that the scale bar under the photo is labeled 1 μm (micrometer). The scale bar works the same way as a scale on a map, wher

AnnZ [28]

Answer:

Hello your question has some missing parts attached below is the complete question

answer : 4 μm

Explanation:

since the scale bar works the same way as a scale on a map , each bar will therefore represent 1 μm and the mature parent cell's is about 4 times the labeled value hence the Mature parent cell diameter will approximately be : 4 μm

8 0

3 years ago