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3 years ago

How can you tell the stigma from the stamens in the flowers

Physics

1 answer:

pishuonlain [190]3 years ago

6 0

Answer:

for wind pollinated flowers they have long feathery stigma that hangs outside the flower while insect pollinated have short stigma that is shorter than even the petals and it's inside the flower

Also thestigma has something that looks like a bulb underneath it and that is the ovary while the stamen is just straight

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A car has a mass of 1520 kg. While traveling at 20 m⁄s, the driver applies the brakes to stop the car on a wet surface with a 0.

docker41 [41]

Answer:

(a)d₁ = 51.02 m

(b)d₂ =51.02m

Explanation:

Newton's second law:

∑F = m*a Formula (1)

∑F : algebraic sum of the forces in Newton (N)

m : mass s (kg)

a : acceleration (m/s²)

Known data

m=1520 kg : mass of the car

μk= 0.4 : coefficient of kinetic friction

g = 9.8 m/s² : acceleration due to gravity

Forces acting on the car

We define the x-axis in the direction parallel to the movement of the car and the y-axis in the direction perpendicular to it.

W: Weight of the block : In vertical direction downward

FN : Normal force : In vertical direction upward

f : Friction force: In horizontal direction

Calculated of the W

W= m*g

W= 1520 kg* 9.8 m/s² = 14896 N

Calculated of the FN

We apply the formula (1)

∑Fy = m*ay ay = 0

FN - Wy = 0

FN = Wy

FN = 14896 N

Calculated of the f

f = μk* N= (0.4)* (14896 N )

f = 5958.4 N

We apply the formula (1) to calculated acceleration of the block:

∑Fx = m*ax , ax= a : acceleration of the block

- f = m*a

-5958.4 = (1520)*a

a = (-5958.4) / ((1520)

a = -3.92 m/s²

(a) displacement of the car (d₁)

Because the car moves with uniformly accelerated movement we apply the following formula to calculate the final speed of the block :

vf²=v₀²+2*a*d₁ Formula (2)

Where:

d:displacement (m)

v₀: initial speed (m/s)

vf: final speed (m/s)

Data:

v₀ = 20 m⁄s

vf = 0

a = --3.92 m/s²

We replace data in the formula (2) to calculate the distance along the ramp the block reaches before stopping (d₁)

vf²=v₀²+2*a*d ₁

0 = (20)²+2*(-3.92)*d ₁

2*(3.92)*d₁ = (20)²

d₁ = (20)² / (7.84)

d₁ = 51.02 m

(b) Different car

m₂ = 1.5 *1520 kg

μk₂= 0.4

W₂= m*g

W₂= (1.5) *1520 kg* 9.8 m/s² = (1.5)*14896 N

FN₂= (1.5)*14896 N

f= 0.4* (1.5)*14896 N

a = - f/m₂ = - 0.4* (1.5)*14896 N /(1.5) *1520

a = -3.92 m/s²

vf²=v₀²+2*a*d₂

vf=0 , v₀=20 m⁄s , a = -3.92 m/s²

d₂ = d₁ = 51.02m

6 0

4 years ago

A physics demo launches a ball horizontally while dropping a second ball vertically at exactly the same time. 1) which ball hits

Simora [160]

Answer:

Both balls will hit the ground at the same time

Explanation:

The factor which leads to ball falling is the gravity acting on the ball;

The motions along the path of both balls are independent and both balls will obey the following illustration

Using the third equation of motion

s = ut + ½at²

Where s = distance covered by both balls.

u = initial velocity of both balls. Since both balls start from rest, u = 0m/s

a = acceleration; and it's equal to acceleration due to gravity.

a = g

By substituton

s = 0 * t + ½gt²

s = 0 + ½gt²

s = ½gt²

Make t the subject of formula

gt² = 2s

t² = 2s/g

t = ±√(2s/g)

But time can't be less than 0 (in other words, negative)

So,

t = √(2s/g)

It'll take both balls √(2s/g) time to hit the floor

6 0

3 years ago

Read 2 more answers

A 1-kg rock is suspended from the tip of a horizontal meterstick at the 0-cm mark so that the meterstick barely balances like a

tigry1 [53]

Explanation:

Given that,

Mass if the rock, m = 1 kg

It is suspended from the tip of a horizontal meter stick at the 0-cm mark so that the meter stick barely balances like a seesaw when its fulcrum is at the 12.5-cm mark.

We need to find the mass of the meter stick. The force acting by the stone is

F = 1 × 9.8 = 9.8 N

Let W be the weight of the meter stick. If the net torque is zero on the stick then the stick does not move and it remains in equilibrium condition. So, taking torque about the pivot.

$9.8\times 12.5=W\times (50-12.5)\\\\W=\dfrac{9.8\times 12.5}{37.5}$

W = 3.266 N

The mass of the meters stick is :

$m=\dfrac{W}{g}\\\\m=\dfrac{3.266}{9.81}\\\\m=0.333\ kg$

So, the mass of the meter stick is 0.333 kg.

5 0

3 years ago

The fine structure for hydrogen atom is

pochemuha

Answer:

When the familiar red spectral line of the hydrogen spectrum is examined at very high resolution, it is found to be a closely-spaced doublet. This splitting is called fine structure and was one of the first experimental evidences for electron spin.

Explanation:

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3 years ago

Which of these statements best describes an effect of changes in Earth's magnetic field?

Sveta_85 [38]

The only statement that makes sense as to which one describes an effect of changes in Earth's magnetic field is the first one - <span>Southern lights are seen at high altitude places like Alaska.
Normally, Southern lights are seen around the South Pole, which means that it is quite odd for them to be seen in Alaska, which is near the North Pole.</span>

6 0

3 years ago

Read 2 more answers

How can you tell the stigma from the stamens in the flowers​

How can you tell the stigma from the stamens in the flowers