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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Roger the turtle moved 450 m in 2 hours the first day and the next day he moved in a straight line at a steady speed of 15 cm/s

Sonja [21]

Answer:

a). Roger travel total a distance of 2070m

b). The average speed of the whole tip $V_{p}$ 0.16025 $\frac{m}{s}$

Explanation:

$V= \frac{x}{t} = \frac{450m}{2 hr} * \frac{1 hr}{3600 s} = \frac{450m}{7200 s}\\ V= \frac{450m}{7200s} =0.125 \\V= 0.0625 \frac{m}{s} \\$

a).

First trip 450m

Second trip :

$V=\frac{x}{t} \\x=V*t \\x= 15 \frac{cm}{s} *3 hr\\x= 15 (\frac{cm}{s}*\frac{1m}{100 cm}) * 3 hr (\frac{3600s}{1hr})\\ x=0.15 \frac{m}{s} * 3600s\\x= 1620 m$

So final distance is

450m+1620m=2070m

b).

$V_{p} = \frac{0.15 \frac{m}{s}+0.0625 \frac{m}{s} }{2} =0.10625 \frac{m}{s}$

The average speed is $V_{p}$ 0.10625 $\frac{m}{s}$

8 0

3 years ago

2. Jenny picks up a guitar and strums. If the sound from the string emanates out at 440 Hz,

erik [133]

Answer:

6.8×10^6 m

Explanation:

f = velocity of light/ wavelength

440= 3×10^8 / wavelength

wavelength = 3×10^7/ 44

= 6.8×10^6 m

7 0

3 years ago

A toy car has a kinetic energy of 8 J. What is its kinetic energy after a frictional force of 0.5 N has acted on it for 6 m?

Nezavi [6.7K]

Answer:

Final kinetic energy, $KE_f=5\ J$

Explanation:

It is given that,

Kinetic energy of toy car, $KE_i = 8\ J$

Frictional force, F = 0.5 N

Distance, d = 6 m

We need to find the kinetic energy after this frictional force has acted on it. We know that frictional force is an opposing force. The work done by the toy car is given by :

$W=F\times d$