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2 years ago

Help me plz.Show workings

Physics

2 answers:

Ksenya-84 [330]2 years ago

8 0

This question is a good example of the difference between 'speed' and 'velocity'. This one is all 'velocity', and you've absolutely gotta keep the directions straight.

The object started out moving forward at 10 m/s. It ended up moving backward at 2 m/s. What was the change in its velocity ?

The change was <u>12 m/s backward</u> !

Momentum = (mass) x (velocity).

Change in momentum = (mass) x (change in velocity)

This change in momentum = (0.1 kg) x (12 m/s backward)

This change in momentum = 1.2 m/s backward or <em>1.2 Ns (B)</em>

ddd [48]2 years ago

3 0

Change in momentum: finial momentum - initial momentum
Momentum = mass * velocity
Mass = 100g, same as 0.1kg
m(v-u) = 0.1(10-2) = 0.1(8)
The answer is 0.8Ns

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A cube of wood having an edge dimension of 20.0cm and a density of 650 kg /m³ floats on water. (b) What mass of lead should be p

schepotkina [342]

The mass added is "m" so the complete cube is submerged in the water is 2.8 kg.

<h3>What mass of lead should be placed on the cube?</h3>

Given: Side of the cube (a) = 20cm

The density of the cube (ρc) = $$$650 kg/m^3$

a) Applying the force balance, the buoyant force must be equal to the weight of the cube

ρcgV = ρg × (Ax)

Substituting the values in the above equation, we get

$(650*(0.2 m)^3)=1000*(0.2 m)^2*x$

x = 0.13

where x is the height of the cube in the water

$$$A = a^2$ is the area of the cross-section

ρ is the density of the water

V is the volume of the cube

Now, the height above the surface of the water would be

h = a − x

Substituting the values, then we get

h = 0.2 − 0.13

h = 0.07 m

b) The mass added is "m" so the complete cube is submerged in the water, therefore

ρcgV + mg = ρg × (V)

$$(650*(0.2 m)^3)+m=1000*(0.2 m)^3$

m = 2.8 kg

The mass added is "m" so the complete cube is submerged in the water is 2.8 kg.

To learn more about buoyant force refer to:

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1 year ago

Why should you rotate food when thawing it 360 training?

Anni [7]

Rotation during thawing is necessary to ensure that your food reaches the right temperature in a secure and efficient manner. This prevents the ice from becoming stuck under some of the food. By rotating it, you can reveal any trapped, covered, or chunked ice.

<h3>What do you mean by Microwave oven?</h3>

A microwave oven, often known as a microwave, is an electric oven that uses electromagnetic radiation with a microwave frequency range to cook and heat food.
As a result, the food is heated via a process known as dielectric heating, which causes the polar molecules there to rotate and produce heat energy.
Because excitation is rather homogenous in the exterior 25–38 mm (1–1.5 inches) of a homogeneous, high water content food item, microwave ovens heat food fast and effectively.

<h3>What are the uses of a microwave oven?</h3>

A microwave oven, sometimes known as an electronic oven, is a device that uses microwaves, which are high-frequency electromagnetic waves, to cook food.
A microwave oven is a compact, box-shaped oven that increases food's temperature by exposing it to an electromagnetic field with a high frequency.

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1 year ago

Two students, standing on skateboards, are initially at rest, when they give each other a shove! After the shove, one student (7

Elden [556K]

Answer:

The other student (59kg) moves right at 7.44 m/s

Explanation:

Given;

mass of the first student, m₁ = 77kg

mass of the second student, m₂ = 59kg

initial velocity of the first student, u₁ = 0

initial velocity of the second student, u₂ = 0

final velocity of the first student, v₁ = 5.7 m/s left

final velocity of the second student, v₂ = ? right

Apply the principle of conservation of linear momentum;

Total momentum before collision = Total momentum after collision

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

(77 x 0) + (59 x 0) = (-77 x 5.7) + (59 x v₂)

0 = - 438.9 + 59v₂

59v₂ = 438.9

v₂ = 438.9 / 59

v₂ = 7.44 m/s to the right

Therefore, the other student (59kg) moves right at 7.44 m/s

6 0

2 years ago

Calculate the total displacement of a mouse walking along a ruler, if it begins at the x=5cm, and then does the following: It wa

Lana71 [14]

<span>To begin, the mouse walks from 5 to 12 cm, for a displacement of 7 cm. Next, it walks 8 cm in the opposite direction, for a total displacement of (7 + [-8]) or (-1) cm. This leaves the mouse on 4 cm, and then it walks from there to the 7cm location, for a displacement of 7-4 or +3 cm. Adding 3cm to -1cm gives a final displacement of +2cm.</span>

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3 years ago

Which phrase desenbes an irregular galaxy ?

Andrews [41]

Answer:

contains many young stars

Explanation:

Irregular galaxies have <em>no definite shape</em>, which means that the first option is incorrect. They are definitely not round.

However,<u> they contain many young stars because the degree of star formation is fast.</u> They also contain old stars. Thus, the second choice is correct.

The "spiral galaxy" is the type of galaxy that has arms that extend from the center. These arms look "spiral," which influenced its name. This makes the last choice incorrect.

They are actually <u>smaller than the other types of galaxies.</u> This makes them <em>prone to collisions</em>. This makes the last choice incorrect.

7 0

2 years ago

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Help me plz.Show workings​

Help me plz.Show workings