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3 years ago

I NEED HELP PLEASE, THANKS!

Physics

1 answer:

Travka [436]3 years ago

6 0

Explanation:

When a person is standing still, the forces acting on them (weight force pulling down and normal force pushing up) are equal and opposite, so the net force is balanced. So the person will continue to be at rest, unless the net force becomes unbalanced.

When a person falls with a parachute, the forces acting on them (weight force pulling down and air resistance pushing up) are equal and opposite, so the net force is balanced. So the person will continue to fall at the same speed until the net force becomes unbalanced.

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The velocity of a motor car moving along a road increases from 10m/s to 50{1} ms in 8s. Find its avarege acceleration. RESULT

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Answer:

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3 years ago

Ultraviolet rays are used to _____.

NeTakaya

Answer:

Grow plants where little light is available

Explanation:

The plants need the ultraviolet rays in order to be able to survive and develop. The need mainly comes from the dependence of these rays for production of food, in a process known as photosynthesis. The plants are producers, thus they create their own food. In order to be able to do that they are using the ultraviolet rays, as well as water, and carbon dioxide. By combining them, the plants manage to create glucose for them, and that is their food source. The plants that are kept at places where there's not enough light are often exposed to ultraviolet rays so that they are able to perform the process of photosynthesis and grow properly.

8 0

2 years ago

Read 2 more answers

A 70.0-kg person throws a 0.0480-kg snowball forward with a ground speed of 33.5 m/s. A second person, with a mass of 55.0 kg, c

saw5 [17]

Answer:

The final velocity of the thrower is $\bf{3.88~m/s}$ and the final velocity of the catcher is $\bf{0.029~m/s}$ .

Explanation:

Given:

The mass of the thrower, $m_{t} = 70~Kg$ .

The mass of the catcher, $m_{c} = 55~Kg$ .

The mass of the ball, $m_{b} = 0.0480~Kg$ .

Initial velocity of the thrower, $v_{it} = 3.90~m/s$

Final velocity of the ball, $v_{fb} = 33.5~m/s$

Initial velocity of the catcher, $v_{ic} = 0~m/s$

Consider that the final velocity of the thrower is $v_{ft}$ . From the conservation of momentum,

$&& m_{t}v_{ft} + m_{b}v_{fb} = (m_{t} + m_{b})v_{it}\\&or,& v_{ft} = \dfrac{(m_{t} + m_{b})v_{it} - m_{b}v_{fb}}{m_{t}}\\&or,& v_{ft} = \dfrac{(70 + 0.0480)(3.90) - (0.0480)(33.5)}{70}\\&or,& v_{ft} = 3.88~m/s$

Consider that the final velocity of the catcher is $v_{fc}$ . From the conservation of momentum,

$&& (m_{c} + m_{b})v_{fc} = m_{b}v_{it}\\&or,& v_{fc} = \dfrac{m_{b}v_{it}}{(m_{c} + m_{b})}\\&or,& v_{fc} = \dfrac{(0.048)(33.5)}{(55.0 + 0.0480)}\\&or,& v_{fc} = 0.029~m/s$

Thus, the final velocity of thrower is $3.88~m/s$ and that for the catcher is $0.029~m/s$ .

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2 years ago

Please help me 5-11 help help

Illusion [34]

Your answer is -6 did that answer your question

5 0

3 years ago

A helicopter, starting from rest, accelerates straight up from the roof of a hospital. The lifting force does work in raising th

LuckyWell [14K]

Answer:

25032.47 W

Explanation:

Power is the time rate of doing work, hence,

P = Work done(non conservative) / time

Work done (non conservative) is given as:

W = total K. E. + total P. E.

Total K. E. = 0.5mv²- 0.5mu²

Where v (final velocity) = 7.0m/s, u (initial velocity) = 0m/s

Total P. E. = mgh(f) - mgh(i)

Where h(f) (final height) = 7.2m, h(i) (initial height) = 0 m

=> W = 0.5mv² - mgh(f)

P = [0.5mv² - mgh(f)] / t

P = [(0.5*790*7²) - (790*9.8*7.2)] / 3

P = (19355 + 55742.4) / 3 = 75097.4/3

P = 25032.47 W

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2 years ago