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IgorC [24]
3 years ago
11

How long Tina, a ballerina, in the air when she leaps straight up with a speed of 1.8 m/s?

Physics
1 answer:
Tems11 [23]3 years ago
3 0

The acceleration of gravity on or near the surface of the Earth is 9.8 m/s².
Anything acted on only by gravity loses 9.8 m/s of upward speed, or gains
9.8 m/s of downward speed, every second.

Leaping straight upward at 1.8 m/s, Tina keeps rising until she runs out of
upward speed.  That happens in (1.8/9.8) = 0.1837 second after the leap.

After that, Finkel's First Law of Motion takes over:
"What goes up must come down."

The dropping part of the leap is symmetrical with the first.  Please don't
make me go through proving it.  Tina hits the floor at the same speed of
1.8 m/s with which she left it, and it takes the same amount of time to drop
from the peak to the floor as it took to rise from the floor to the peak.

So her total time out of contact with the floor is

                     2 x (0.1837 sec)  =  0.367 second  (rounded)

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An air craft heads north at 320 km/hr relative to the wind. the wind velocity is 80km/hr from the north. find the relative veloc
Gnoma [55]

Answer:

Relative to the ground, the velocity of the aircraft is 240 km/hr

Explanation:

Relative velocity is different from normal velocity;

When 2 objects are moving in opposite directions towards each other, they will appear to be faster than they actually are;

This is known as the relative velocity;

The information tells us we have the aircraft moving 320 km/hr northwards relative to the wind;

The wind is in the opposite direction at 80 km/hr;

R = relative velocity of the aircraft

v = actual velocity of the aircraft

w = velocity of the wind

R = v + w

Note: if the wind was moving in the same direction, the formula would be R = v - w

320 = v + 80

v = 320 - 80

v = 240

The velocity relative to the ground is simply the actual velocity as the ground doesn't move;

So, relative to the ground, the velocity of the aircraft is simply 240 km/hr

7 0
2 years ago
Estimate the order of magnitude of the length, in
Scrat [10]
A) a mouse, to an order of magnitude = 0.1 m ( a tenth of a meter ) That would be a big mouse but the alternatives are 1 meter or one hundredth of a meter... so go with 1/10th 

<span>b) Easy = 1 meter </span>

<span>c) two choices 10m or 100 m . Go with 100 m </span>

<span>d) Stretch it out , trunk tip to tail tip - call it 10 m </span>

<span>e) Your choice 100 m or 1000 m..... These are estimates. So long as you are within one order of magnitude you can't really be given wrong. So I'd say 100m</span>
8 0
3 years ago
Models of four atoms are shown as figures A, B, C, and D. Which two atoms represent isotopes of the same element?
timurjin [86]
C and d have the same amount of protons and electrons
3 0
2 years ago
When dots are printed from a laser printer to form letters, they must be close enough so that you do not see the individual dots
balandron [24]

Answer: separate them

Explanation:

3 0
3 years ago
An alternating voltage of 25.0 V is connected across the primary coil of a transformer.
uranmaximum [27]

Answer:

A

Explanation:

Wattage = E * I

E = 25

I = 5

Wattage = 25 * 5

Wattage = 125

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125/50 = I

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7 0
2 years ago
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