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2 years ago

3 help with physics!! ---------------- will give brainliest

Physics

1 answer:

Zinaida [17]2 years ago

6 0

Answer:

Answer B

Explanation:

An increase in resistance makes it harder for the electric current to pass through

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Two sacks contain the same number of identical apples and are separated by a distance r. The two sacks exert a gravitational for

stepan [7]

Answer:

Explanation:

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3 years ago

A sound wave was determined to have a frequency of 0.3 Hz, speed of 150 cm/s, and amplitude of 2 cm. Find its wavelength.

fredd [130]

Answer:

5 m

Explanation:

From the question,

v = λf....................... Equation 1

Where v = speed of the sound wave, λ = wavelength of the sound wave, f = frequency of the sound wave.

make λ the subject of the equation

λ = v/f..................... Equation 2

Given: v = 150 cm/s = 1.5 m/s, f = 0.3 hz.

Substitute these values into equation 2

λ = 1.5/0.3

λ = 5 m.

7 0

3 years ago

Tudy the images about geologic time.

Inessa [10]

Answer:

The first flowering plants appeared in the Mesozoic era, not the Paleozoic era.

Explanation:

The Mesozoic era was an era where numerous organisms started to develop in very unique and more advanced ways, both the animals and the plants. In the last period of the Mesozoic, the Cretaceous, the first flowering plants started to appear on the scene. This was revolutionary trait of the plants, and soon these plants started to occupy more and more space and became one of the dominant organisms on the planet. Other important evolution that took place in this period are the appearance of the dinosaurs and the mammals, both becoming the dominant animals on the planet, first the dinosaurs, after that the mammals.

8 0

3 years ago

Read 2 more answers

21) A youngster having a mass of 50.0 kg steps off a 1.00 m high platform. If she keeps her legs fairly rigid and comes to rest

zlopas [31]

Answer:

-22,150 N

Explanation:

When the youngster jumps off the platform, during the fall her initial potential energy is converted into kinetic energy, according to the law of conservation of energy. Therefore, we can write:

$mgh=\frac{1}{2}mu^2$

where the term on the left is the potential energy while the term on the right is the kinetic energy, and where

m = 50.0 kg is the mass of the youngster

$g=9.8 m/s^2$ is the acceleration due to gravity

h = 1.00 m is the heigth of the platform

u is the speed of the youngster as she reaches the floor

Solving for u,

$u=\sqrt{2gh}=\sqrt{2(9.8)(1.00)}=4.43 m/s$

Then, when the youngster hits the floor, the force exerted on her during the deceleration is given by:

$F=\frac{\Delta p}{\Delta t}=\frac{m(v-u)}{\Delta t}$

where $\Delta p$ is her change in momentum, and where

m is the mass

v = 0 is the final velocity (she comes to a stop)

u = 4.43 m/s is the initial velocity

$\Delta t=10.0 ms =0.010 s$ is the duration of the collision

Substituting,

$F=\frac{(50.0)(0-4.43)}{0.010}=-22150 N$

And the negative sign means the direction of the force is opposite to the motion (so, upward).

6 0

3 years ago

A toolbox of mass 3.2kg is lowered by a rope from the roof to the ground. Find the acceleration of the toolbox when the force of

Lisa [10]

Answer:

The answer to your question is:

a) 2.7 m/s²

b) -3.6 m/s²

Explanation:

Data

mass of the toolbox = 3.2 kg

a = ?

F = 40 N and F = 20 N

g = 9.81 m/s²

Formula

Second law of motion = F = ma

a + g = F / m

a = F/m - g

a) a = 40/3.2 - 9.81

a = 2.69 ≈ 2.7 m/s² positive up

b) a = 20/ 3.2 - 9.81

a = 6.25 - 9.81

= - 3.56 ≈ - 3.6 m/s² negative down

8 0

3 years ago