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4 years ago

When a person floating in swimming pool, they experience an upthrust. what causes this effect?

1 answer:

6 0

When your head sticks out of the water the upthrust reduces as your head is no longer displacing water, and there is 0 resultant force so you float at that level. hope this helps, can i get brainliest please

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Find the force needed to lift a 3000 N weight using a machine with a mechanical advantage of 15.

Soloha48 [4]

IF the machine is 100% efficient, then you only need to push at the input with a force of 200 Newtons. BUT ... you have to keep pushing the 200N 15 times as far as you want to lift the big weight.

8 0

3 years ago

Read 2 more answers

The acceleration of gravity at the surface of Moon is 1.6 m/s2 . A 5.0 kg stone thrown upward on Moon reaches a height of 20 m.

kramer

Answer:

(a) 8 m/s

(b) 5 s

Explanation:

(a)

Using,

V² = U²+2gh ......................... Equation 1

Where V = final velocity, U = Initial velocity, g = acceleration due to gravity on the surface of the moon, h = height reached.

Given: V = 0 m/s ( At it's maximum height), g = -1.6 m/s² ( as its moves against gravity), h = 20 m.

Substitute into equation 1

0 = U²+[2×20×(-1.6)]

-U² = - 64

U² = 64

U = √64

U = 8 m/s.

(b)

V = U +gt.................... Equation 2

Where t = time to reach the maximum height.

Given: V = 0 m/s ( At the maximum height), g = -1.6 m/s² ( Moving against gravity), U = 8 m/s.

Substitute into equation 2

0 = 8+(-1.6t)

-8 = -1.6t

-1.6t = -8

t = -8/-1.6

t = 5 s.

5 0

3 years ago

A group of air particles in a balloon are spread far apart and moving rapidly around inside the balloon. The balloon is placed i

Slav-nsk [51]

Answer:

1) The balloon will shrink

2) The balloon will grow bigger and regain its shape

Explanation:

By the kinetic theory of gases, we have;

$v_{rms} = \sqrt{\dfrac{3 \cdot R \cdot T}{MW} }$

$P = \dfrac{n \cdot MW \cdot vrms^2}{3 \cdot V}$

Where;

$v_{rms}$ = RMS Speed

R = The universal gas constant

T = The temperature

MW = The Molecular weight

n = The number of moles

V = The volume

P = The pressure

1) When the balloon is placed in the refrigerator for minutes, the temperature inside the balloon will drop and RMS speed will reduce, however due to the elastic wall of the balloon, the pressure will remain the same therefore the volume will reduce and the balloon will shrink

2) When the balloon is placed on the kitchen counter, the temperature inside the balloon will rise leading to the increase in the RMS speed which will raise the pressure effect on the wall of the balloon as the balloon is made of elastic material, as the pressure rises, the wall expands to keep the pressure constant and the volume occupied by the air particles will increase, the balloon will grow bigger and regain its shape.

6 0

3 years ago

A 70kg car drives through a curve with radius 50m. What is the minimum angle the road should be tilted to keep the car on the ro

worty [1.4K]

when car moves along a circular path then centripetal force for taking turn will be provided by the component of normal force

Let the road is tilted by some angle

so force equations are given as

$F_n cos\theta = mg$

$F_n sin\theta = \frac{mv^2}{R}$

now divide two equations

$tan\theta = \frac{v^2}{Rg}$

now as it is given to us that

$v = 80 km/h$

$v = 80* \frac{5}{18} = 22.2 m/s$

$R = 50 m$

now we have

$tan\theta = \frac{22.2^2}{50*9.8}$

$tan\theta = 1$

$\theta = tan^{-1}1$

$\theta = 45^0$

so it is inclined at an angle of 45 degree

8 0

3 years ago

the primary of a transformer connected to 170v has 10 turns. the secondary has 70 turns. find voltage. this is a step down trans

Nikolay [14]

No it isn't. (Unless you connect it backwards.)

If the primary has 10 turns and the secondary has 70 turns,
then the voltage that appears across the secondary is
7 times the voltage that you feed to the primary.

If you're 'exciting' the primary with 170 volts, then you need
to be cautious around the secondary terminals, because there's
1,190 volts there !

If you want to use your transformer in a step-down configuration,
you can certainly connect it up the other way around.

Feed the 170 volts to the winding with 70 turns. You've reversed
the labels 'primary' and 'secondary', and that's OK. The voltage
at the terminals of the 10-turn winding will be (170/7) = 24.3 volts.

4 0

4 years ago

When a person floating in swimming pool, they experience an upthrust. what causes this effect?​

When a person floating in swimming pool, they experience an upthrust. what causes this effect?