Help with both questions I’ll mark brainliest

Answer:

D

Explanation:

The net force is the combination of all forces acting on an object.

Answer:

f=m*a

Explanation:

The formula for force says force is equal to mass (m) multiplied by acceleration (a)

Answer:

Explanation:

 a )

Time for first ball to reach top position

v = u - gt

0 = vi - gt

t = vi / g

Time to reach balcony  while going downwards

= vi /g

Total time = 2 vi / g

Time to go down further to the ground = t₁

Total time = 2 vi / g + t₁

Time for the other ball to go to the ground = t₁

Time difference = ( 2 vi / g + t₁ ) - t₁

= 2vi / g .

( b )

v² = u² + 2gh

For both the throw ,

final displacement = h , initial velocity downwards = vi

( For the first ball also  , when it go down while passing the balcony , it acquires the same velocity vi but its direction is downwards.)

vf² = vi² + 2gh

vf = √ ( vi² + 2gh )

(c )

displacement of first ball after time t

s₁ = - vi t + 1/2 g t²  [ As initial velocity is upwards , vi is negative ]

displacement of second ball after time t

s₂ = vi t + 1/2 g t²

Difference = d =  s₂ - s₁

= vi t + 1/2 g t² - ( - vi t + 1/2 g t² )

d = 2 vi t .

Answer:

The person who did the comment is correct, it B - Dew will form on leaves

Explanation:

Answer:

B

Explanation:

Valeriie.07 tap in g

Answer:

F= m x a

Explanation:

Force (f) = mass (m) x acceleration (a)

Answer:

Δx = 0.7 m

Explanation:

       [tex]t = \sqrt{\frac{2*1.8m}{ 9.8m/s2} } = 0.6 s (2)[/tex]

       [tex]\Delta x = v_{o} * t = 1.1 m/s* 0.6 s = 0.7 m (3)[/tex]

Answer:

A basketball sitting still in a players hands

Explanation:

The other 3 answers have the ball in motion (going towards the basket, bouncing, and rolling) so that would be kinetic energy.

When the basketball is sitting in the player's hands, it has the potential to be in motion.

Answer:

it is D not B it D

Explanation:

Answer You need to consider that the gravity on earth is 9.8 m/s/s. This means any object you let go on the earths surface will gain 9.8 m/s of speed every second. You need to apply a force on the object in the opposite direction to avoid this acceleration. If you are pushing something up at a constant speed, you are just resisting earths acceleration. The more massive and object is, the greater force is needed to accelerate it. The equation is Force = mass*acceleration. So for a 2kg object in a 9.8 m/s/s gravity you need 2kg*9.8m/s/s = 19.6 Newtons to counteract gravity. Work or energy = force * distance. So to push with 19.6 N over a distance of 2 meters = 19.6 N*2 m = 39.2 Joules of energy. There is an equation that puts together those two equations I just used and it is E = mgh

The amount of Energy to lift an object is (mass) * (acceleration due to gravity) * (height)

:Hence, the Work done to life the mass of 2 kg to a height of 10 m is 196 J. Hope it helps❤️❤️❤️

Explanation:

Answer:

impulse equals the average net external force multiplied by the time this force acts. It is equal to the change in momentum.

Explanation:

Answer:

v = 7.95 m/s

Explanation:

Given that,

Wavelength of a wave, [tex]\lambda=53\ cm=0.53\ m[/tex]

Frequency of a wave, f = 15 Hz

We need to find the speed of the wave. The speed of a wave is given by :

[tex]v=f\lambda\\\\v=15\ Hz\times 0.53\ m\\\\v=7.95\ m/s[/tex]

So, the wave move with a speed of 7.95 m/s.

Answer:

changing the direction in which a force is exerted

Answer:

b

Explanation:

this because if force (f) are resultant cos then the point is proportional to the direction of c at greatest possible forces

Answer:

The magnitude of the car's acceleration as it slows during braking is 36.81 m/s²

Explanation:

From the question, the given values are as follows:

Initial velocity, u = 90 m/s

final velocity, v = 0 m/s

distance, s = 110 m

acceleration, a = ?

Using the equation of motion, v² = u² + 2as

(90)² + 2 * 110 * a = 0

8100 + 220a = 0

220a = -8100

a = -8100/220

a = -36.81 m/s²

The value for acceleration is negative showing that car is decelerating to a stop. The magnitude of the car's acceleration as it slows during braking is therefore 36.81 m/s²

Answer:

Explanation:

For circular motion of stone the formula is

v = ω R where ω is angular velocity , v is linear velocity .

For first motion ,

R = length of sling = .6 m

ω = 2π n , n is no of revolution per second

ω = 2 x 3.14 x 5 = 31.4 rad /s

v = 31.4 x .6 = 18.84 m /s

For second  motion ,

R = length of sling = .9 m

ω = 2π n , n is no of revolution per second

ω = 2 x 3.14 x 5 = 31.4 rad /s

v = 31.4 x .9 = 28.26  m /s

Answer:

it would be downwards due to gravitational force

Answer:

(A) By reducing friction

Answer:

A

Explanation:

Answer:

1767Kw

Explanation:

Velocity of wind = 10 m/s

diameter of the blades= 60m

ρ= air density = 1.25 kg/m3

Acceleration due to gravity= 9.81 m/s^2

Mechanical energy of the wind can be calculated using the expression below

Energy= (e*m)

= ρ V A e............eqn(1)

Where A= area

ρ= air density

e= wind energy per unit mass of air

e= (v^2)/2..........eqn(2)

If we substitute the values into eqn (2) we have

e= [(10)^2]/2

=50J/Kg

But Area=A= (πd^2)/4

Area= ( π× 60^2)/4

Area=2827.8m^2

If we input substitute the values into eqn (1) we have

Energy= 1.25 ×10 × 50×2827.8

=1767145.7W

We can convert to kilo watt

=1767145.7W/ 1000

= 1767Kw

Hence, the mechanical energy of air per unit mass and the power generation potential of a wind turbine is 1767Kw

Answer:

FRICTION

Explanation:

Friction is a force, the resistance of motion when one object rubs against another.

Frictional force

Explanation:

Its the opposing force against horizontal motion

Explanation:

time = distance / velocity

We know that distance = 910 km and velocity = 90 km/h.

t = d / v

t = 910 km / 90 km/h

t = 10.11 hrs

The object traveled for 10.11 hours long. Hope this helps, thank you !!

Answer:

The answer is below

Explanation:

The resistivity of copper is ρ = 1.72 * 10⁻⁸ Ωm, diameter d = 10 cm = 0.1 m

The resistance (R) of transmission line is given as:

Rtl = ρL / A; where ρ = resistivity of copper = 1.72 * 10⁻⁸ Ωm, L = length of transmission line = 2000 km = 2000000 m, A is the area of the wire = πd²/4 = π(0.1)²/4

[tex]R_{tl}=\frac{\rho L}{A}=\frac{1.72*10^{-8}*2000000}{\pi*0.1^2/4}=4.4 \ ohm[/tex]

Power = [tex]\frac{V_L^2}{R_L}[/tex]

Power = 10 MW = 10 * 10⁶ W

[tex]10*10^6=\frac{(250*10^3)^2}{R_L} \\\\R_L=\frac{(250*10^3)^2}{10*10^6} \\\\R_L=6250\ ohm[/tex]

[tex]I_L=\frac{V_L}{R_L} \\\\I_L=\frac{250*10^3}{6250} =40\ A[/tex]

a) Since there are two tranmission lines, the power consumed by the lines is:

[tex]P_{TL}=2*I_L^2*R_{TL}=2*40^2*4.4=14080\ W[/tex]

b) The energy generated by the source = 10 * 10⁶ W + 14080 W = 10014080 W

Fraction used = 10 * 10⁶ / 10014080 * 100% = 99.86%

Answer:

The correct option is c. 75 for this question

Explanation:

The correct option is c. 75 for this question:

Let's see how.

Continuity Equation is given as:

AcVc = AaVa

Where,

Aa = Area of Aorta

Ac = Area of the capillary

Va = Fluid speed in Aorta

Vc = Fluid speed in Capillary

So,

Assuming the fluid is the ideal one/

[tex]\pi[/tex]/4 [tex]Dc^{2}[/tex] Vc= [tex]\pi[/tex]/4 [tex]Da^{2}[/tex] Va

[tex]Dc^{2}[/tex] Vc= [tex]Da^{2}[/tex] Va

Dc = Da x [tex]\sqrt{\frac{Va}{Vc} }[/tex]

Dc = 2.5 cm x [tex]\sqrt{\frac{60 cm}{0.07 cm } }[/tex]

Dc = 73.192 cm

Dc = 75 approximately

Hence, the diameter of the capillary = 75 cm approximately  

Vab= E = 20V

because I = 0 and the voltage drop across the resistances R1 and R2 is also 0.

Second circuit:

Vab = 10V (no voltage drop across R1)

Vcd= E2-E1 = 20V

Series connection of voltage sources. But the sources are connected to the contrary and voltage drop across R1 or R2 is 0 V.

Answer:

the answer is D

Explanation:

Mass extinctions were first identified by the obvious traces they left in the fossil record. ... Such dramatic changes in adjacent rock layers make it clear that mass extinctions were geologically rapid and suggest that they were caused by catastrophic events (e.g., a period of intense volcanic activity).

Mass extinction events wiped out many species at the same time resulting in older rock layers having more fossil variety than younger rock layers.

Mass extinction events are events which resulted in the mass death of many species of organisms.

Mass extinction events are presumed to have occurred in the past as seen from gaps in the fossils records.

Mass extinction events are thought to have occurred through intense volcanic activity in a particular area.

A mass extinction event in the fossil record will show an older layer of rock containing a much greater variety of fossils than a slightly younger layer of rock does.

Therefore, mass extinction events wiped out many species at the same time.

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Answer:

The tree is 143.325 meters tall

Explanation:

The given parameters of the eucalyptus tree are;

The mass of the eucalyptus tree nut = 1.7 ounces

The speed of the nut at 50.3 m above the ground, v = 42.7 m/s

The equation for free fall is given as follows;

v² = 2·g·h

Where;

v = The velocity after falling through a height, h

g = The acceleration due to gravity = 9.8 m/s²

h = The height through which the seed has already fallen

Therefore, we have;

h = v²/(2·g) = (42.7 m/s)²/(2 × 9.8 m/s²) = 93.025 m

The height through which the seed has already fallen, h = 93.025 m

The height of the tree = h + The height of the seed above ground at the moment it was falling at 42.7 m/s

The height of the tree = 93.025 m + 50.3 m = 143.325 m

The height of the tree = 143.325 m.

The height of the eucalyptus tree is approximately 111.9 meters.

To determine the height of the tree, we can use the equations of motion. The initial velocity of the nut, u, is 0 m/s (since it is dropped), the acceleration due to gravity, a, is approximately 9.8 m/s², and the final velocity, v, is 42.7 m/s. We need to find the height, h. Using the equation v² = u² + 2a(h - u), we can rearrange it to solve for h: h = (v² - u²) / (2a) Plugging in the values, we get: h = (42.7² - 0²) / (2 * 9.8) = 111.9 meters Therefore, the height of the eucalyptus tree is approximately 111.9 meters.

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Answer:

b)  k Δx - W cos θ - μ mg cos θ = m a ,  c)  θ = 86.6º, d)  Δx = 1.18 m

Explanation:

a) In the attachment we can see a diagram of the forces in this problem and the coordinate axes for its decomposition.

F is the force applied by the spring, while it is compressed, this force disappears when the block leaves the spring

b) Let's apply Newton's second law for when the spring is compressed

let's use trigonometry to break down the weight

            sin θ = Wₓ / W

            cos θ = W_y / W

             Wₓ = W sin θ

             W_y = W cos θ

Y axis  

               N - W_y = 0

               N = W_y

               N = W cos θ

X axis

           F -Wₓ -fr = ma

the force applied by the spring is given by hooke's law

           F = k Δx

friction force has the expression

           fr = μ N

           fr = μ W cos θ

we substitute

            k Δx - W cos θ - μ mg cos θ = m a           ( 1)

c) If the plane has no friction, what is the angle so that Δx = 0.1m

We write the equation 1, with fr = 0 and since the system is still a = 0

            k Δx - W cos θ -0 = 0

            cos θ = [tex]\frac{k \Delta x}{ m g}[/tex]

            cos θ = [tex]\frac{880 \ 0.1}{ 150 \ 9.8}[/tex]

            cos θ = 0.0598

            θ = cos⁻¹ 0.0598

            θ = 86.6º

d) In this part they give the angle θ = 45º and there is no friction, they ask the compression

the acceleration is zero, we substitute in 1

            k Δx - W cos θ - 0 = 0

            Δx = [tex]\frac{mg \ cos \ \theta}{k}[/tex]

            Δx = [tex]\frac{ 150 \ 9.8 \ cos45}{880}[/tex]

            Δx = 1.18 m