A swimmer pushes backwad on water with their hand...what force allows the swimmer to move forward?

Athlete’s foot is also called...

Aliun [14]

Answer:

Your answer is: D) Tinea Pedis

Explanation:

Hope this helped : )

6 0

3 years ago

An ambulance with a siren emitting a whine at 1800 hz overtakes and passes a cyclist pedaling a bike at 2.23 m/s. after being pa

Anna71 [15]

It's the Doppler Effect that "up and down sound."

I was on Yahoo--- Brainly doesn't have an option for Credientials or Site credit, so I'll just put this in the quotes:

The formula for doppler effect is always (s is speed and f is frequency): 
f_perceived.by.observer = f_of.emitted.wave * (s_wave + s_observer) / (s_wave + s_source.of.wave) 

And you should pay attention to the signs: 
s_observer is positive if the receiver is moving towards the source, negative otherwise 
s_source.of.wave is positive if the source is moving away from the observer, negative otherwise 

Applying it to this case: 

s_source.of.wave = ? (positive), speed of ambulance 
s_observer = + 2.44 m/s speed cyclist 
f_of.emitted.wave =1800 Hz frequency of whine 
f_perceived.by.observer = 1760 frequency heard by cyclist 
s_wave = 343 m/s speed of sound in air 

Now you know every value in the equation for doppler effect except by s_source.of.wave, so you can solve for s_source.of.wave.

5 0

2 years ago

A 4.0 kg object will have a weight of approximately 14.8 N on Mars. What is the gravitational field strength on Mars?

zhannawk [14.2K]

Field strength =force/unit mass
= 14.8N/ 4kg = 3.7N/kg

8 0

3 years ago

Read 2 more answers

Two students were climbing stairs at school. Student 1 has a weight of 700 N. Student 2 has a weight of 650 N. How much power wo

KIM [24]

Student 1 would have a power 467 W and student 2 would have a power of 433 W. The correct option is the fourth option - Student 1 would have 467 W, and Student 2 would have 433 W of power.

From the question,

We are to calculate the power each student would have to climb the flight of stairs.

Power can be calculated using the formula

$P = \frac{F \times d}{t}$

Where

P is Power

F is the force

d is the distance

and t is the time

NOTE: The weight of the students represent the force

For student 1

F = 700 N

d = 4 m

t = 6 s

∴ $P = \frac{700 \times 4}{6}$

P = 467 W

For student 2

F = 650 N

d = 4 m

t = 6 s

∴ $P = \frac{650 \times 4}{6}$

P = 433 W

Hence, Student 1 would have a power 467 W and student 2 would have a power of 433 W. The correct option is the fourth option - Student 1 would have 467 W, and Student 2 would have 433 W of power.

Learn more here: brainly.com/question/18801566

3 0

2 years ago

A tennis ball is a hollow sphere with a thin wall. It is set rolling without slipping at 4.03 m/s on the horizontal section of a

seraphim [82]

Answer:

2.38 m/s, 4.31 m/s, lower

Explanation:

a)

Initial energy = final energy

½ m v₀² + ½ I ω₀² = mgh + ½ m v₁² + ½ I ω₁²

Since the ball is rolling without slipping, ω = v / r.

For a hollow sphere, I = ⅔ m r².

½ m v₀² + ½ (⅔ m r²) (v₀ / r)² = mgh + ½ m v₁² + ½ (⅔ m r²) (v₁ / r)²

½ m v₀² + ⅓ m v₀² = mgh + ½ m v₁² + ⅓ m v₁²

⅚ m v₀² = mgh + ⅚ m v₁²

⅚ v₀² = gh + ⅚ v₁²

v₀² = 1.2gh + v₁²

v₁ = √(v₀² − 1.2gh)

Given v₀ = 4.03 m/s, g = 9.80 m/s, h = 0.900 m:

v₁ = √((4.03)² − 1.2 (9.80) (0.900))

v₁ ≈ 2.38 m/s

At the top of the loop, the sum of the forces in the radial direction is:

∑F = ma

W + N = m v² / R

N = m v² / R - mg

N = m (v² / R - g)

Given v = 2.38 m/s, R = 0.450 m, and g = 9.80 m/s²:

N = m ((2.38)² / 0.450 - 9.80)

N = 2.77m

N ≥ 0, so the ball stays on the track.

b)

Initial energy = final energy

Borrowing from part a):

v₂ = √(v₀² − 1.2gh)

This time, h = -0.200 m:

v₂ = √((4.03)² − 1.2 (9.80) (-0.200))

v₂ ≈ 4.31 m/s

c)

Without the rotational energy:

½ m v₀² = mgh + ½ m v₁²

½ v₀² = gh + ½ v₁²

v₀² = 2gh + v₁²

v₁ = √(v₀² - 2gh)

This is less than v₁ we calculated earlier.

6 0

3 years ago